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Advanced RF, Microwave Engineering, and High-Power Microwave Sources
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Advanced RF, Microwave Engineering, and High-Power Microwave Sources

A special issue of Electronics (ISSN 2079-9292). This special issue belongs to the section "Microwave and Wireless Communications".

Deadline for manuscript submissions: closed (30 April 2024) | Viewed by 27119

Special Issue Editors

Dr. Sohail Mumtaz

E-Mail Website
Guest Editor
Electrical and Biological Physics, Kwangwoon University, Seoul 01897, Korea
Interests: high power microwaves; virtual cathode oscillator; particle-in-cell simulation; basic plasma diagnostics; nonthermal plasma; reactive species; microwave biological interaction; radiation biology; efficiency improvement of microwave sources; pulse power sources; gyrotrons, magnetrons, klystrons, backward wave oscillators, vacuum tubes; RF antenna; terahertz sources; metamaterials; intense relativistic electron beams; millimeter-waves; vircators; power beaming; ultra-wide band; microwave emission modes
Dr. Syed Muzahir Abbas

E-Mail Website
Guest Editor
Electrical and Electronic Engineering, Macquarie University, Macquarie Park, NSW 2109, Australia
Interests: antennas; electromagnetics; carbon nanotubes; wearable; 3d printing; high-impedance surfaces; frequency-selective surfaces; 5G; mmWave; millimeter wave; PDMS; high gain; base station; UHF; VHF; beam steering
Special Issues, Collections and Topics in MDPI journals
Dr. Pradeep Lamichhane

E-Mail Website
Guest Editor
School of Engineering, Warwick University, Coventry CV4 7AL, UK
Interests: microwave; microwave plasma; nonthermal plasma; nitrogen fixation; plasma source designing; plasma agriculture; plasma diagnostics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Microwaves are a form of non-ionizing radiation with wavelengths and frequencies ranging from 1m to 1 mm and 300 MHz to 300 GHz, respectively. RF/microwave systems are essential in all current wireless communication and a wide range of applications such as industries, military, households, accelerators, communication, astronomy, spectroscopy, and the medical profession. It is not an overstatement to say that RF/microwave technologies impact every area of our lives; they are everywhere, from the wireless doorbell to keyless entrance into our automobiles, from cooking to industrial heating, from cell phones to computer systems, and from medical to space technology. This massive penetration of RF/microwave systems in our modern life has been facilitated by large and quick technical advancements at many levels. If the microwave power exceeds the peak power of 100 MW it is known as high power microwave (HPM). Developing high-power microwave technology might help with a variety of applications, including space and satellite missions, increasing the detection range of radar technology, communication systems, power beaming, linear collider, fusion heating, electronic warfare, and serving as a nonlethal weapon in military use. Unfortunately, the majority of HPM sources generate microwaves with low device efficiency, which is why boosting efficiency is an ongoing subject of research in this issue.

This Special Issue of the MDPI journal Electronics entitled "Advanced RF, Microwave engineering, and high-power microwave sources" invites innovative papers, with a particular emphasis on current advances in the analysis, design, implementation, designing, and measurement of RF and microwave circuits and sources. A wide range of studies based on RF, microwave, and wireless technologies, such as RF transceivers, power dividers/combiners, antennas, wireless power transfer, energy harvesting, high power microwave generation, particle-in-cell simulation, microwave mode analysis, RF plasma, pulsed power technologies, vacuum tubes, millimeter-waves, terahertz sources, and so on, are of interest of this issue. Authors are encouraged to submit both regular research articles and well-written review articles.

Dr. Sohail Mumtaz
Dr. Syed Muzahir Abbas
Dr. Pradeep Lamichhane
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Electronics is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • radio frequency
  • microwave generation
  • pulsed power technology
  • virtual cathode oscillators
  • particle-in-cell simulation
  • microwave sources
  • RF plasma
  • RF circuits
  • microwave imaging
  • device efficiency
  • vacuum tubes
  • RF antenna
  • terahertz sources
  • millimeter-waves
  • metamaterials
  • magnetic mirror
  • intense relativistic electron beams

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Published Papers (14 papers)

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14 pages, 8770 KiB  
Communication
Design Techniques for Wideband CMOS Power Amplifiers for Wireless Communications
by Milim Lee, Junhyuk Yang, Jaeyong Lee and Changkun Park
Electronics 2024, 13(9), 1695; https://doi.org/10.3390/electronics13091695 - 27 Apr 2024
Cited by 1 | Viewed by 935
Abstract
In this study, we designed a wideband CMOS power amplifier to support multi-band and multi-standard wireless communications. First, an input matching technique through LC network and a wideband design technique using a low Q-factor transformer were proposed. In addition, a design technique was [...] Read more.
In this study, we designed a wideband CMOS power amplifier to support multi-band and multi-standard wireless communications. First, an input matching technique through LC network and a wideband design technique using a low Q-factor transformer were proposed. In addition, a design technique was proposed to improve output matching using RC feedback. To verify the feasibility of the proposed design methodology for wideband CMOS power amplifiers, the designed power amplifier was fabricated using a 180 nm RFCMOS process. The size including all of the matching network and test pads was 1.38 × 0.90 mm2. In addition, the effectiveness of the proposed power amplifier was verified through the measured results using modulated signals of WCDMA, LTE, and 802.11n WLAN. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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12 pages, 2857 KiB  
Article
A Compact Circular Waveguide Directional Coupler for High-Order Mode Vacuum Electronic Devices
by Tao Zhu, Wenjie Fu, Dun Lu, Yibo Pan, Chuannan Li, Lin He, Haoxuan Sun and Yang Yan
Electronics 2024, 13(3), 633; https://doi.org/10.3390/electronics13030633 - 2 Feb 2024
Viewed by 987
Abstract
In this paper, a compact circular waveguide directional coupler for high-order mode vacuum electronic devices is presented and investigated. To reduce the size, the primary and secondary waveguides of this coupler are connected in an orthogonal way by two coupling holes. Moreover, to [...] Read more.
In this paper, a compact circular waveguide directional coupler for high-order mode vacuum electronic devices is presented and investigated. To reduce the size, the primary and secondary waveguides of this coupler are connected in an orthogonal way by two coupling holes. Moreover, to improve the directivity and operating bandwidth, a method of loading adjustable metal stubs on the isolating port is proposed and introduced in design. A Ka-band TE01-mode circular waveguide directional coupler was designed, and the structure parameters were optimized by electromagnetic simulation. To verify the design, a prototype sample was fabricated, assembled, and tested. The experimental results show good agreement with the simulations, and the directivity are improved by adjusting the metal stubs on the isolating port. In the experiment, a 26.7 dB directivity at 35 GHz was obtained, and the bandwidth of directivity above 20 dB was higher than 7 GHz, corresponding to a relative bandwidth higher than 20%. Meanwhile, the TE01° mode maintained good transmission efficiency in this compact high-order mode directional coupler. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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20 pages, 2443 KiB  
Article
Adjacent-Channel Compatibility Analysis of International Mobile Telecommunications Downlink and Digital Terrestrial Television Broadcasting Reception in the 470–694 MHz Frequency Band Using Monte Carlo Simulation
by Hussein Taha, Péter Vári and Szilvia Nagy
Electronics 2024, 13(3), 575; https://doi.org/10.3390/electronics13030575 - 31 Jan 2024
Cited by 1 | Viewed by 1013
Abstract
This paper delves into the imperative need for coexistence and compatibility in the 470–694 MHz frequency band, as mandated by the World Radiocommunication Conference 2015 (WRC-15) and the WRC-23. It focuses on challenges in the coexistence of Digital Terrestrial Television Broadcasting (DTTB) and [...] Read more.
This paper delves into the imperative need for coexistence and compatibility in the 470–694 MHz frequency band, as mandated by the World Radiocommunication Conference 2015 (WRC-15) and the WRC-23. It focuses on challenges in the coexistence of Digital Terrestrial Television Broadcasting (DTTB) and International Mobile Telecommunications-2020 (IMT-2020) services in downlink-only mode, particularly in adjacent-channel scenarios. Using Monte Carlo simulations, the study evaluates the probability of interference from IMT base stations with DTTB reception. The analysis thoroughly investigates the impact of the IMT transmitter’s Adjacent Channel Leakage Ratio (ACLR) and the DTTB receiver’s Adjacent-Channel Selectivity (ACS) on the probability of interference. The results demonstrate a significant degradation in the DTTB reception probability at the edge of coverage based on standard assumptions. To address these challenges, this paper provides recommendations for mitigating interference. These include defining enhanced ACLR regulations for IMT base stations, implementing antenna discriminations, providing specialized filters, and establishing national coordination procedures. The research provides valuable insights for informed decision making in spectrum management within the 470–694 MHz band, aiming to facilitate the coexistence of DTTB and IMT-2020 services, in line with international regulations and best practices. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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16 pages, 7666 KiB  
Article
Study of Ultra-Broadband Synthesizer of Fast Indirect Type in a 0.5–18 GHz Range for SIGINT System
by Yuseok Jeon
Electronics 2024, 13(1), 48; https://doi.org/10.3390/electronics13010048 - 21 Dec 2023
Cited by 2 | Viewed by 1113
Abstract
In the present study, a new structure (0.5–18 GHz) with excellent phase noise characteristics and a fast switching speed is proposed. Ultra-wideband synthesizers with low phase noises and less spurious signals have been developed to be used as local oscillators and for built-in [...] Read more.
In the present study, a new structure (0.5–18 GHz) with excellent phase noise characteristics and a fast switching speed is proposed. Ultra-wideband synthesizers with low phase noises and less spurious signals have been developed to be used as local oscillators and for built-in test (BIT) functions in the field of electronic warfare systems (EW), in which synthesizers are installed at the front-end of devices; this is accomplished by applying an SMT process using a packaged-type device. This paper compares the advantages and disadvantages of PLVCO (old) and DDS reference sources (new) based on two types of frequency synthesizers. At this time, different frequencies can be output from the two ports by different FPGA coding of the internal frequency plan according to the operating frequency. The main RF line will be made a dielectric substrate, RO4350, with a relative dielectric constant of 3.38 and a dielectric thickness of 0.508 mm. In the ultra-broadband synthesizer module, the phase noise of the DDS output (1.25 GHz) was −131 dBc/Hz at 10 KHz offset. The phase noise in the 18 GHz output is expected to be −105.9 dBc/Hz at 1 KHz offset. In particular, by proposing a structure for obtaining a wideband frequency using a single source (DDS), the structure secures reliability from the point of view of a system operating for a long time by implementing a similar circuit within a predictable range. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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15 pages, 8014 KiB  
Article
A Novel High-Power Rotary Waveguide Phase Shifter Based on Circular Polarizers
by Qinghe Zhuang, Feng Yan, Zhengfeng Xiong, Meng Yang and Min Liu
Electronics 2023, 12(13), 2963; https://doi.org/10.3390/electronics12132963 - 5 Jul 2023
Cited by 2 | Viewed by 1758
Abstract
This paper presents a novel high-power rotary waveguide phase shifter based on circular polarizers specifically engineered for high-power microwave (HPM) applications. The phase shifter is capable of performing a precise 360° linear phase shift through rotation and consists of three parts: a linearly [...] Read more.
This paper presents a novel high-power rotary waveguide phase shifter based on circular polarizers specifically engineered for high-power microwave (HPM) applications. The phase shifter is capable of performing a precise 360° linear phase shift through rotation and consists of three parts: a linearly polarized to left-handed circularly polarized (LP-LHCP) mode converter, a left-handed to right-handed circularly polarized (LH-RHCP) mode converter, and a linearly polarized to right-handed circularly polarized (LP-RHCP) mode converter. This paper analyzes the phase-shifting principle, optimizes the three parts of the X-band rotary waveguide phase shifter, and conducts simulation studies on the entire phase shifter, which is made of aluminum. The results show that the reflection is less than −20 dB and the insertion loss is below 0.3 dB within 9.5 GHz to 10.2 GHz. The phase shift is equal to twice the rotation angle within this frequency range. Specifically, the phase shifter can achieve a linear phase shift of 360° when rotated from 0° to 180°, with a maximum deviation of less than 1.2°. Moreover, the power-handling capacity of the phase shifter in vacuum exceeds 242 MW. In the meantime, a prototype of a phase shifter was manufactured, and the experimental results are in good agreement with the simulation results. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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15 pages, 5580 KiB  
Article
A Comprehensive Overview of the Temperature-Dependent Modeling of the High-Power GaN HEMT Technology Using mm-Wave Scattering Parameter Measurements
by Giovanni Crupi, Mariangela Latino, Giovanni Gugliandolo, Zlatica Marinković, Jialin Cai, Gianni Bosi, Antonio Raffo, Enza Fazio and Nicola Donato
Electronics 2023, 12(8), 1771; https://doi.org/10.3390/electronics12081771 - 8 Apr 2023
Cited by 9 | Viewed by 3183
Abstract
The gallium-nitride (GaN) high electron-mobility transistor (HEMT) technology has emerged as an attractive candidate for high-frequency, high-power, and high-temperature applications due to the unique physical characteristics of the GaN material. Over the years, much effort has been spent on measurement-based modeling since accurate [...] Read more.
The gallium-nitride (GaN) high electron-mobility transistor (HEMT) technology has emerged as an attractive candidate for high-frequency, high-power, and high-temperature applications due to the unique physical characteristics of the GaN material. Over the years, much effort has been spent on measurement-based modeling since accurate models are essential for allowing the use of this advanced transistor technology at its best. The present analysis is focused on the modeling of the scattering (S-) parameter measurements for a 0.25 μm GaN HEMT on silicon carbide (SiC) substrate at extreme operating conditions: a large gate width (i.e., the transistor is based on an interdigitated layout consisting of ten fingers, each with a length of 150 μm, resulting in a total gate periphery of 1.5 mm), a high ambient temperature (i.e., from 35 °C up to 200 °C with a step of 55 °C), a high dissipated power (i.e., 5.1 W at 35 °C), and a high frequency in the millimeter-wave range (i.e., from 200 MHz up to 65 GHz with a step of 200 MHz). Three different modeling approaches are investigated: the equivalent-circuit model, artificial neural networks (ANNs), and gated recurrent units (GRUs). As is shown, each modeling approach has its pros and cons that need to be considered, depending on the target performance and their specifications. This implies that an appropriate selection of the transistor modeling approach should be based on discerning and prioritizing the key features that are indeed the most important for a given application. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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11 pages, 6587 KiB  
Article
Experimental Study of RF–Plasma Interaction Using a Low-Pressure DC Glow Discharge Tube for MPC
by Asif Mehmood Khan, Muhammad Mansoor Ahmed and Umair Rafique
Electronics 2023, 12(3), 551; https://doi.org/10.3390/electronics12030551 - 20 Jan 2023
Cited by 1 | Viewed by 2601
Abstract
This paper aims to perform experimental validation of RF–plasma interaction behaviors for the purposes of wave transmission and reflection. Wave reflection from plasma is of interest as it finds applications in pulse compression and RF polarizer-based systems. Simulations are performed using a combination [...] Read more.
This paper aims to perform experimental validation of RF–plasma interaction behaviors for the purposes of wave transmission and reflection. Wave reflection from plasma is of interest as it finds applications in pulse compression and RF polarizer-based systems. Simulations are performed using a combination of Magic3D and COMSOL multiphysics to characterize the plasma–wave interaction and discharge tube properties. The goal is to generate plasma with characteristics that wholly reflect the incident electromagnetic wave. A glass tube of inner diameter 22 mm and length 100 mm, with 12 mm brass electrodes, is fabricated for plasma generation. Argon-based DC glow discharge is sustained at 500 volts at a pressure of 3.8 Torr. Plasma density is calculated to be 2.529×1019 m−3, with a corresponding plasma frequency of 7.18 GHz. Due to this higher frequency, a 3 GHz incident RF wave is reflected, as measured through S-parameter measurements using a network analyzer. Off and on states of the tube correspond to S11=−40 dB and S11=−13 dB, which show wave transmission and reflection, respectively. When the plasma column is ignited, the reflected wave has a phase difference of 180∘. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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10 pages, 2368 KiB  
Article
Magnetic Field Testing Technique of System-Generated Electromagnetic Pulse Based on Magnetoresistance Effects
by Yifei Liu, Wei Wu, Jinxi Li, Mo Zhao, Feng Wei, Shuqing Ren and Tao Huang
Electronics 2023, 12(3), 492; https://doi.org/10.3390/electronics12030492 - 17 Jan 2023
Cited by 1 | Viewed by 1747
Abstract
To address the technical challenges of system-generated electromagnetic pulse (SGEMP) measurement, the generation environment of SGEMP is introduced, and the characteristics of the magnetic field waveform to be measured are analyzed first in this paper. Then a magnetoresistance-based SGEMP measurement method is proposed [...] Read more.
To address the technical challenges of system-generated electromagnetic pulse (SGEMP) measurement, the generation environment of SGEMP is introduced, and the characteristics of the magnetic field waveform to be measured are analyzed first in this paper. Then a magnetoresistance-based SGEMP measurement method is proposed for the first time. Aiming at the problem that the high frequency response of the existing commercial magnetoresistance chips cannot meet the test requirements, a pulsed magnetic field detector with strong anti-interference ability is developed in this work based on the tunneling magnetoresistance (TMR) sensor chip developed by Lanzhou University and a high-gain amplifier circuit with common mode rejection and a good shielding structure. It can be shown from the calibration results that the detector sensitivity factor is 4.0 nT/mV and the measurable pulse front is greater than or equal to 28 ns, which meet the requirements of SGEMP magnetic field waveform measurement. Based on the developed detector, the ideal test waveform is obtained under the “Flash II” hard X-ray pulse source through a reasonable experimental design. The related work has laid a foundation for validating the numerical calculation model and further mastering the propagation law and effect mechanism of SGEMP. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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13 pages, 7315 KiB  
Article
A CC-Type IPT System Based on S/S/N Three-Coil Structure to Realize Low-Cost and Compact Receiver
by Lin Yang, Shuai Shao, Haiting Wu, Shuai Jiang and Li Zhang
Electronics 2023, 12(2), 463; https://doi.org/10.3390/electronics12020463 - 16 Jan 2023
Cited by 1 | Viewed by 1527
Abstract
The characteristics of load-independent constant current (CC) output and zero phase angle (ZPA) operation are required in many scenarios of inductive power transfer (IPT) applications. However, the existing topologies with CC output characteristics usually need to introduce additional compensation components on the receiving [...] Read more.
The characteristics of load-independent constant current (CC) output and zero phase angle (ZPA) operation are required in many scenarios of inductive power transfer (IPT) applications. However, the existing topologies with CC output characteristics usually need to introduce additional compensation components on the receiving side to compensate for reactive power and achieve the preset function. This not only increases the occupied space of the receiving side, but also increases the cost and weight. Therefore, this study proposes a new IPT system based on an S/S/N three-coil structure. The proposed system can achieve the CC output function and an operation nearly ZPA and zero-voltage switching (ZVS) through flexible parameter design. Moreover, there are no compensation components on the receiving side of the proposed system, which guarantees a low-cost, lightweight, and compact receiver. Firstly, a comprehensive analysis of the proposed S/S/N three-coil structure IPT system that implements CC output characteristics and ZPA operation is provided. Then, the conditions for realizing ZVS are discussed in terms of parameter design and the sensitivity of CC output characteristics to the changes in compensation capacitance parameters. Furthermore, the proposed S/S/N three-coil structure IPT system is compared with previous related studies to reflect its advantages. Finally, the correctness of the theory is verified by simulation and experiment. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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13 pages, 2714 KiB  
Article
Calculation and Analysis of Characteristic Parameters for Lossy Resonator
by Jian Cui, Yu Yu and Yuanyao Lu
Electronics 2023, 12(1), 7; https://doi.org/10.3390/electronics12010007 - 20 Dec 2022
Cited by 1 | Viewed by 1692
Abstract
Resonator is widely employed in microwave and millimeter-wave fields. However, it is challenging and crucial to calculate the electromagnetic field distribution in the resonant cavity with various loss dielectrics. In this paper, according to the axisymmetric distribution characteristics of the lossy resonator, the [...] Read more.
Resonator is widely employed in microwave and millimeter-wave fields. However, it is challenging and crucial to calculate the electromagnetic field distribution in the resonant cavity with various loss dielectrics. In this paper, according to the axisymmetric distribution characteristics of the lossy resonator, the electromagnetic function of each part in the cavity is established with the Borgnis function, the characteristic equation is obtained based on the mode-matching method, and the resonance frequency and Q factor of the eigenmode TM010 are numerically calculated. With the proposed method, the impact of various dielectric structures and characteristics parameters on the resonant properties of the TM010 mode may be thoroughly examined by taking into account the influence of the thickness as well as the materials of the lossy layer in the z direction. The relative error between the theoretical and the simulated results is below 0.7% at different structures and lossy dielectrics, which indicates that the general calculation approach, as well as crucial data and structure references, is suitable for a related device design in TM010 mode. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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14 pages, 3046 KiB  
Article
Reduced-Cost Optimization-Based Miniaturization of Microwave Passives by Multi-Resolution EM Simulations for Internet of Things and Space-Limited Applications
by Anna Pietrenko-Dabrowska, Slawomir Koziel and Ali Ghaffarlouy Raef
Electronics 2022, 11(24), 4094; https://doi.org/10.3390/electronics11244094 - 8 Dec 2022
Cited by 3 | Viewed by 1477
Abstract
Stringent performance specifications along with constraints imposed on physical dimensions make the design of contemporary microwave components a truly onerous task. In recent years, the latter demand has been growing in importance with the innovative application of areas such as the Internet of [...] Read more.
Stringent performance specifications along with constraints imposed on physical dimensions make the design of contemporary microwave components a truly onerous task. In recent years, the latter demand has been growing in importance with the innovative application of areas such as the Internet of Things coming into play. The need to employ full-wave electromagnetic (EM) simulations for response evaluation, reliable, yet CPU-heavy, only aggravates the issue. This paper proposes a reduced-cost miniaturization algorithm that employs a trust-region search procedure and multi-resolution EM simulations. In our approach, the resolution of the EM model is adjusted throughout the optimization process based on its convergence status starting from the lowest admissible fidelity. As the algorithm converges, the resolution is increased up to the high-fidelity one, used at the final phase to ensure reliability. Four microwave components have been utilized as verification structures: an impedance matching transformer and three branch-line couplers. Significant savings in terms of the number of EM analyses required to conclude the size reduction process of 41, 42, 38 and 50 percent have been obtained (in comparison to a single-fidelity procedure). The footprint area of the designs optimized using the proposed approach are equal to 32, 205, 410 and 132 mm2, in comparison to 52, 275, 525 and 213 mm2 of the initial (and already compact) design. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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11 pages, 4318 KiB  
Article
The Characteristics of the Second and Third Virtual Cathodes in an Axial Vircator for the Generation of High-Power Microwaves
by Sohail Mumtaz and Eun-Ha Choi
Electronics 2022, 11(23), 3973; https://doi.org/10.3390/electronics11233973 - 30 Nov 2022
Cited by 7 | Viewed by 2175
Abstract
A virtual cathode oscillator or vircator is a vacuum tube for producing high-power microwaves (HPM). The efficiency of the vircator has been a difficult task for decades. The main reasons for low efficiency are intense relativistic electron beam (IREB) loss and few or [...] Read more.
A virtual cathode oscillator or vircator is a vacuum tube for producing high-power microwaves (HPM). The efficiency of the vircator has been a difficult task for decades. The main reasons for low efficiency are intense relativistic electron beam (IREB) loss and few or no interactions between IREB and HPM. In this case, forming multiple virtual cathodes may be beneficial in overcoming these constraints. By reusing the axially propagating leaked electrons (LE), we could confine them and form multiple virtual cathodes (VCs). This article discussed the characteristics of newly formed VCs based on simulation results. The formation time of new VCs was discovered to be highly dependent on the reflector position and the density of LE approaching their surfaces. Furthermore, multiple VC formation in the waveguide region does not affect conventional VCs’ position or forming time. The emission mode of the generated HPM was TM01 with single and multiple VCs and remained unaffected. The formation of multiple VCs positively influenced the axial and radial electric fields. When compared to a single VC, the axial and radial electric field increased 25.5 and 18 times with multiple VCs. The findings suggested that forming multiple VCs could be a future hope for achieving high vircator efficiency. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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17 pages, 7958 KiB  
Article
Design of the Radio Frequency Section of a Ka-Band Multiple Beam Ladder-Type Extended Interaction Klystron
by Santigopal Maity, Madutha Santosh Kumar, Chaitali Koley, Debashish Pal and Ayan Kumar Bandyopadhyay
Electronics 2022, 11(22), 3781; https://doi.org/10.3390/electronics11223781 - 17 Nov 2022
Viewed by 1850
Abstract
Ka-band frequencies are becoming increasingly popular due to their application potential in high-data-rate wireless communications relevant to 5G applications, satellite link establishment, etc. High-power amplifiers in this frequency band, offering several tens of watts of output RF power, are one of the main [...] Read more.
Ka-band frequencies are becoming increasingly popular due to their application potential in high-data-rate wireless communications relevant to 5G applications, satellite link establishment, etc. High-power amplifiers in this frequency band, offering several tens of watts of output RF power, are one of the main enabling components of these communication systems. This article reports the design studies and analysis of the radio frequency (RF) section of a multiple beam-extended interaction klystron (MB-EIK). The proposed multiple beam RF section with a ladder-type EIK structure offers several crucial features, such as a low-voltage operation, moderate operational bandwidth, and high output power. Starting from the design of the intermediate cavities, the input and output sections and the overall RF section are presented. The proposed RF section supports the operation at 28.5 GHz center frequency with about a 500 MHz 3 dB bandwidth employing four electron beams with a 4 kV DC accelerating field. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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12 pages, 948 KiB  
Article
Electrical Characterization of Through-Silicon-via-Based Coaxial Line for High-Frequency 3D Integration (Invited Paper)
by Zhibo Zhao, Jinkai Li, Haoyun Yuan, Zeyu Wang, Giovanni Gugliandolo, Nicola Donato, Giovanni Crupi, Liming Si and Xiue Bao
Electronics 2022, 11(20), 3417; https://doi.org/10.3390/electronics11203417 - 21 Oct 2022
Cited by 4 | Viewed by 2597
Abstract
Through-silicon-via (TSV)-based coaxial line techniques can reduce the high-frequency loss due to the low resistivity in the silicon substrate and thus can improve the efficiency of vertical signal transmission. Moreover, a TSV-based coaxial structure allows easily realizing the impedance matching in RF/microwave systems [...] Read more.
Through-silicon-via (TSV)-based coaxial line techniques can reduce the high-frequency loss due to the low resistivity in the silicon substrate and thus can improve the efficiency of vertical signal transmission. Moreover, a TSV-based coaxial structure allows easily realizing the impedance matching in RF/microwave systems for excellent electrical performance. However, due to the limitations of existing available dielectric materials and the difficulties and challenges in the manufacturing process, ideal coaxial TSVs are not easy to obtain, and thus, the achieved electrical performance might be unexpected. In order to increase the flexibility of designing and manufacturing TSV-based coaxial structures and to better evaluate the fabricated devices, modeling and analysis theories of the corresponding high-frequency electrical performance are proposed in the paper. The theories are finally well validated using the finite-element simulation results, hereby providing guiding rules for selecting materials and improving manufacturing techniques in the practical process, so as to optimize the high-frequency performance of the TSV structures. Full article
(This article belongs to the Special Issue Advanced RF, Microwave Engineering, and High-Power Microwave Sources)
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