Groove Gap Waveguide Research Articles

A gap waveguide-based mechanically reconfigurable phase shifter for high-power Ku-band applications

This paper presents a novel design of a low-loss, reconfigurable broadband phase shifter based on groove gap waveguide (GGW) technology. The proposed phase shifter consists of a folded GGW and three bends with a few pins forming the GGW and one bend attached to a movable plate. This movable plate allows for adjustments to the folded waveguide length, consequently altering the phase of electromagnetic waves. The advantage of GGW technology is that it does not require electrical contact between different parts of a structure. Therefore, it enables the moving parts to slide freely without electromagnetic energy leakage, resulting in improved insertion loss in high-power applications. In addition, in the proposed design, the position of the input and output waveguide ports of the phase shifter remains fixed, which is advantageous from a practical point of view. As shown by measurement and simulation results, there is nearly 37% impedance bandwidth with the highest insertion loss of 0.6 dB, and the developed device has a maximum phase shift of 770° at the center frequency of 13 GHz. The phase shifter can be used for various radar and satellite applications that require phase control, such as beamforming networks and phased array antennas.

Preface

The purpose of the three-day 2024 3rd International Conference on Electronic Information and Communication Engineering (EICE 2024), held via virtual form during January 12th to 14th, 2024 in Guangzhou China, was to create a timely forum for multi-disciplinary discussions related to the recent developments on electronic information and communication engineering. As usual, the program of the conference mainly consisted of keynote speeches, oral and poster presentations, with the former including speeches delivered by three sophisticated professors from related research areas. The keynote speeches are: i) Recent Progress of Millimeter-wave Circuits Using Groove Gap Waveguide Technology given by Prof. Wenjie Feng (South China University of Technology, China); ii) 6G Satellite-ground Massive MIMO Communication: Key Technologies and Development Prospect given by Prof. Zhiyong Luo (Sun Yat-sen University, China); iii) Artificial Intelligence (AI)-Enhanced Wireless Network: Further Developments and Future Outlooks given by Assoc. Prof. Feng Ke (South China University of Technology, China). In the framework of experimental and theoretical approaches, the Conference gathered about 100 delegates from all over the world and addressed a number of highly relevant aspects of electronic information and communication engineering. Covering topics on Microelectronics and Solid-State Electronics, Sixth Generation Mobile Communication Technology (6G), Communication Electronic Circuit and Technology, Information and Communication Engineering, Digital Signal Processing, etc., the selected contributions of this volume provide guidance for future interdisciplinary developments in related fields. We received quantities of manuscripts of invited papers and other contributions presented at the Conference. All of these papers have gone through a rigorous peer review process and are collected in the Conference Proceedings. We would like to thank all the anonymous colleagues who acted as referees to assess the suitability of the various articles for publication in Journal of Physics: Conference Series. We are confident that the high quality of both invited and contributed papers contained in this Proceedings will be appreciated by relevant industries and communities. On behalf of the conference EICE 2024 organizing committee, we would like to express our deeply appreciation to all the keynote speakers, oral speakers, peer reviewers, and all the participants and supporters. More than anything, we would like to acknowledge the Journal of Physics: Conference Series, for the efforts and help of all its staff in publishing this paper volume. The Committee of EICE 2024 List of Committee Member is available in this Pdf.

3-D printed triple-band metasurface filter based on groove gap waveguide technology

This article proposes a 3-D printed high selectivity triple-band metasurface bandpass filter (BPF) for millimeter-wave applications using groove gap waveguide (GGW) technology. Firstly, the metasurface composed of electromagnetic bandgap elements in GGW technology is designed and analyzed. This configuration effectively mitigates radiation and electromagnetic wave leakage. Subsequently, the multimode split-type topology under the resonances of TE102 and TE201 modes is utilized to realize a triple-band bandpass response with a compact circuit size. Additionally, the TE101 mode considered as an extra energy coupling path is used to introduce more transmission zeros (TZs). Finally, the design prototype is fabricated using 3D printing technology. The measured results are in good agreement with the simulated ones, providing an excellent option for mm-wave wireless communication systems.

3-D Screen Printing: Efficient Additive Manufacturing of Groove Gap Waveguide Filters in D-Band

3-D Screen Printing: Efficient Additive Manufacturing of Groove Gap Waveguide Filters in <i>D</i>-Band

Preface

In recent years, many delegates turned their attention to the fields of energy and power and put forward a series of constructive suggestions and recommendations on promoting the healthy development of the new energy generation industry and the green and low-carbon development of power, for example, “Building a new power system with new energy as the main body is an important task in the process of hitting carbon peak and attaining carbon neutrality, and new energy power generation will become the main force of future power supply.”In order to bring in the latest progress in theory, technology and application in the fields of energy and power at home and abroad in recent years, and show the latest research achievements, 2023 5th International Conference on Energy, Power and Grid (ICEPG 2023) was held in Guangzhou, China from September 22nd to 24th, 2023. It was attended by about 200 participants worldwide.The Conference presented an outstanding program of papers covering the most recent advances in energy and power, including Nuclear Engineering and Hydrogen Energy Resources, Power System Protection, Operation and Control, Power Quality and Electromagnetic Compatibility, Integrated Optics and Electro-Optical Devices, etc. The papers in this Proceedings published by Journal of Physics: Conference Series (JPCS) represent a collection of the invited speeches and other contributions.At this meeting we had a comprehensive overview of this fascinating field and of future scenarios thanks to the participation of distinguished delegates around the globe. The Conference was presided by Dr. Ziyu Chen from South China University of Technology, China. Professor Jizhong Zhu (South China University of Technology, China), the Conference Chair, first delivered an opening speech and then a keynote speech on Digital Power Grid Technology and Applications. What’s more, Prof. Wenjie Feng (South China University of Technology, China) performed a speech on Recent Progress of Millimeter-wave Circuits Using Groove Gap Waveguide Technology, Prof. Zhou Wu (Chongqing University, China) on Recurrent Neural Networks: Theoretical and Application Progress, and Assoc. Prof. Mahdi Deimi Dasht Bayaz (ITMO University, Russia) on Feasibility and Comparison of Using Integrated Solar-Base Systems for a Sample Residential Building in Various Climate Conditions. The participants raised questions based on the speeches and interacted with the speakers and people around, leading to a heated discussion on the latest research findings and trends in related fields.We would like to thank all the participants, especially those who contributed speeches, posters and manuscripts, for making ICEPG 2023 such an exciting and memorable conference. We thank the members of Technical Program Committee for putting together so outstanding a program. Finally, we acknowledge the staff of JPCS for their tireless efforts in the preparation of this volume, and all our colleagues whose friendly and efficient service contributed much to the success of the Conference.The Committee of ICEPG 2023List of Committee Member is available in this pdf.

A High-Resolution Microwave Displacement Sensor Based on Interferometry in Groove Gap Waveguide Technology

A High-Resolution Microwave Displacement Sensor Based on Interferometry in Groove Gap Waveguide Technology

Millimeter-wave Quasi-elliptic Filters in Groove Gap Waveguide Technology Using Overmoded Cavity with Spurious Coupling Suppression for Next-generation SATCOM Applications

Millimeter-wave Quasi-elliptic Filters in Groove Gap Waveguide Technology Using Overmoded Cavity with Spurious Coupling Suppression for Next-generation SATCOM Applications

Ka-band diplexer design based on half-mode groove gap waveguide

This paper shows the practical design of a Ka-band tuning-less diplexer in half-mode groove gap waveguide (HM-GGW) technology for multi-beam satellite applications. This new technology can be easily manufactured, since it lets the design of two separate metallic pieces: one for the cover with periodic pins, and another one for the half-groove gap waveguide structure. The proposed diplexer is composed of two bandpass HM-GGW filters, an H-plane T-junction and the corresponding transitions to the input/output WR28 rectangular ports. To illustrate how this technology can be applied, a prototype has been successfully fabricated, showing in-band measured return and insertion losses of 21 dB and 0.87 dB in the lower band, 16 dB and 0.86 dB in the upper band, and a good isolation level (better than 32.5 dB) in the whole operational frequency range.

Design of dual-mode dual-band filter based on multilayer groove gap waveguide

This paper presents a novel dual-mode dual-band filter (DBF) based on multilayer groove gap waveguide (GGW). Unlike other published planar GGW filters, the proposed filter achieves a vertically stacked duplicate topology by introducing a rectangular aperture in the common wall and traditional inductive irises on the same layer, with perfect central symmetry in the overall structure. This reduces machining difficulty while having a smaller size. By optimizing the dimensions of the coupling structure and rectangular cavities, dual-mode resonators (DMRs) including even mode and odd mode are used to accomplish dual-bandpass response. Additionally, an efficient transition is presented and applied to achieve a good impedance matching from rectangular waveguide (RW) to GGW. To better demonstrate, a multilayer DBF with working center frequencies of 67.9 and 69.8 GHz is designed, fabricated and measured. Good consistency can be observed between the simulation result and the measurement result.

Dual‐band bandpass filter with high selectivity based on 3D printable groove gap waveguide

AbstractA compact dual‐band bandpass filter (BPF) with high selectivity based on 3D printable groove gap waveguide (GGW) for millimeter application is proposed by the authors. Two stacked dual‐mode GGW resonant cavities including TE102 and TE201 are used to realise a compact structure. The dual‐band bandpass response of the GGW BPF is developed from a split‐type coupling topology which produced two transmission zeros (TZs) between the two passbands. In addition, two TZs are generated outside the two passbands after introducing a source‐load coupling, which achieves a higher frequency selectivity. For verification, a prototype is designed, fabricated and measured. The measured results agree well with the simulated ones, which validates the proposal.

Compact Wideband Groove Gap Waveguide Bandpass Filters Manufactured with 3D Printing and CNC Milling Techniques.

This paper presents for the first time a compact wideband bandpass filter in groove gap waveguide (GGW) technology. The structure is obtained by including metallic pins along the central part of the GGW bottom plate according to an n-order Chebyshev stepped impedance synthesis method. The bandpass response is achieved by combining the high-pass characteristic of the GGW and the low-pass behavior of the metallic pins, which act as impedance inverters. This simple structure together with the rigorous design technique allows for a reduction in the manufacturing complexity for the realization of high-performance filters. These capabilities are verified by designing a fifth-order GGW Chebyshev bandpass filter with a bandwidth BW = 3.7 GHz and return loss RL = 20 dB in the frequency range of the WR-75 standard, and by implementing it using computer numerical control (CNC) machining and three-dimensional (3D) printing techniques. Three prototypes have been manufactured: one using a computer numerical control (CNC) milling machine and two others by means of a stereolithography-based 3D printer and a photopolymer resin. One of the two resin-based prototypes has been metallized from a silver vacuum thermal evaporation deposition technique, while for the other a spray coating system has been used. The three prototypes have shown a good agreement between the measured and simulated S-parameters, with insertion losses better than IL = 1.2 dB. Reduced size and high-performance frequency responses with respect to other GGW bandpass filters were obtained. These wideband GGW filter prototypes could have a great potential for future emerging satellite communications systems.

A Wideband Full-Metal Sidewall-Loaded Magnetoelectric Dipole Array Based on Combined Ridge and Groove Gap Waveguides in the Q-Band

A wideband full-metal sidewall-loaded magnetoelectric (ME) dipole array antenna fed by combined ridge-groove gap waveguide is proposed. Three promising full-metal aperture-coupled 2×2-element ME-dipole subarrays are investigated and compared in detail. By introducing sidewalls around the metal pillars and increasing their height to 0.36λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , the bandwidth of the subarray is substantially enhanced to 33% for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> < -15 dB. An eigenmode analysis is performed to explain and validate the broadband property of the proposed subarray with taller pins and sidewalls. The combined ridge gap waveguide and E-plane groove gap waveguide are employed in the feeding layer for a compact array as well as for lower losses and better isolation between the gap waveguides. Wideband ridge-to-groove (RG) and groove-to-ridge (GR) junctions are designed using stepped transformers for bandwidth enhancement. For verification, an 8×8-element sidewall-loaded ME-dipole array is designed and fabricated by computer numerical controlled (CNC) milling technique in the Q-band. The bandwidth for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> < -10 dB is widened to 35.9% from 34.5 to 49.4 GHz. From 34.3 GHz to 34.7 GHz and 35.6 GHz to 48.7 GHz, the antenna efficiency is better than 75%, with a bandwidth of 32.5%. The proposed design is attractive for wideband and higher-frequency wireless applications.

Half-Height Pin Gap Waveguide-Based Slow-Wave Structure for Millimeter Wave Traveling-Wave Tubes

The design of a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{W}$</tex-math> </inline-formula> -band traveling-wave tube (TWT) power amplifier based on a groove gap waveguide (GW) slow-wave circuit is presented in this article. The technology of GW is analyzed to aid the design of electromagnetic band gap-based slow-wave structures (SWSs) in the upper millimeter wave range of the spectrum while alleviating some of the typical fabrication challenges at these frequencies. The results of particle-in-cell (PIC) simulations numerically demonstrate a 10-GHz instantaneous 3-dB bandwidth in the range 89–99 GHz with a minimum power gain of 25 dB. A prototype of the complete SWS is manufactured via computer numerical control (CNC) machining and measured to verify the cold simulation results. Machining tolerances and surface roughness are also investigated. The design approach via groove GW is flexible and can be extended to alternative rectangular waveguide-based SWSs.

A Circular-Polarization-Reconfigurable Holographic Leaky-Wave Antenna With Fixed-Frequency Beam-Scanning Property

A fixed-frequency beam-scanning leaky-wave antenna (LWA) with circular-polarization (CP) reconfigurable property operating in Ka band is developed in this letter. A groove gap waveguide (GGW) structure is adopted for feeding and transmission, and 64 CP patches are excited through the cross-shaped slots etched over the GGW. By switching the conditions between “ON” and “OFF” of the PIN diodes, these exciting slots can act as either transverse slots or longitudinal slots, and hence to realize the transition between left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP). Meanwhile, the fixed-frequency beam-scanning characteristic is achieved by manipulating the hologram, which is controlled by the activation states of diodes. Finally, the presented fabrication is taken into experiment to verify its performance, and an agreement can be observed in the simulated and experimental results. The eventual peak gains reach 13.4 dBic in the LHCP state and 12.1 dBic in the RHCP state, respectively. In addition, a beam-scanning range up to 100° between -50° and 50°is realized with desirable CP reconfigurable performance between LHCP and RHCP.

Wideband Circularly Polarized mm-Wave Array Antenna Using H-Shaped Low-Axial-Ratio Apertures

An H-shaped all-metal radiating element comprising an active and a coupled slot has been proposed to design wideband high-efficiency circularly-polarized antenna arrays. The proper excitation of several modes on the coupled slot enables a wide axial ratio bandwidth with high circular polarization purity. In order to feed an array of such radiating elements, a simple and scalable two-layer corporate network, implemented in groove gap waveguide technology, is conceived. Those good frequency properties have been confirmed by the fabrication of a prototype, whose experimental results report a 1-dB axial ratio bandwidth of 22%. In addition, a peak radiation efficiency of 97% with good pattern stability, and an impedance bandwidth of 21% with high return loss, have been measured. The high circular polarization purity demonstrated by these wideband apertures makes them particularly suitable for Ka-band satellite communications antennas.

Fully Metallic Luneburg Metalens Antenna in Gap Waveguide Technology at V-Band

This article presents the design of a flat Luneburg metalens antenna at V-band using gap waveguide (GW) technology. The metalens consists of a parallel plate waveguide (PPW) loaded with metallic pins whose height is modulated to get an effective refractive index that follows the Luneburg equation. A Groove GW (GGW) H-plane horn is used to illuminate the metalens, such that the rays are collimated and a planar wavefront is generated in the direction of propagation. Since the structure at hand is planar, it can be efficiently integrated on flat surfaces. Moreover, the fully metallic structure is mechanically robust and presents lower losses than lenses including dielectric substrates. A prototype has been fabricated and tested, simulations and experimental results are in very good agreement. The metalens yields an input reflection coefficient ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{11}$ </tex-math></inline-formula> ) below −10 dB from 45 to 70 GHz, whereas the −3 dB gain fractional bandwidth is 26.2% with respect to a center frequency of 60 GHz, with a peak of 22.5 dB at 61 GHz. These features make this design an interesting solution for millimeter-wave (MMW) applications.

Design of evanescent mode band-pass filters based on groove gap waveguide technology

This paper proposes for the first time a design method of Chebyshev band-pass filters based on groove gap waveguide (GGW) technology and evanescent mode. The evanescent mode GGW section has been implemented by decreasing the width of the groove area by means of two additional rows of metallic pins, and the filter structure has been obtained by inserting resonators of metallic pins along the central part of this narrower GGW section according to a coupling matrix synthesis method. The proposed method has allowed reducing the analysis number of this band-pass filter during the design process and the computation cost with the electromagnetic (EM) simulator, solving the discretization problem of the different lengths of the evanescent mode section. This design technique has been applied to a fourth-order Chebyshev band-pass GGW filter. The design has been performed in the recommended band of the WR75 standard (10 GHz – 15 GHz). The design specifications have been a central frequency f0=12 GHz, a fractional bandwidth FBW = 2.5 % and return loss RL = 20 dB. Measurement and electromagnetic (EM) simulation results have shown a good agreement. Return and insertion losses in the pass-band region of the measured prototype have been, respectively, RL = 20 dB and IL = 0.3 dB, while maximum attenuation in the stop-band regions reached ASB = 83 dB. A comparison has been performed between the measured prototype and other GGW band-pass filters. The proposed GGW band-pass filter has been shown to have reduced size and high-performance characteristics. Future emerging communications systems could benefit from this evanescent mode GGW Chebyshev band-pass filter.

A Fixed-Frequency Beam-Scanning Leaky-Wave Antenna Using Phase and Amplitude Control for Millimeter-Wave Applications

A new type of fixed-frequency beam-scanning leaky-wave antenna (LWA) in Ka millimeter-waveband is developed in this article, based on dual control of phase and amplitude. The antenna consists of a groove gap waveguide (GGW) and 80 perturbation units. Each unit contains one patch and a pair of H-shaped slots. By controlling the state of a slot with p-i-n diodes, the phase of the radiated field from each unit can be switched between two opposite phases, called “1” state and “−1” state, while the magnitude of the radiated field remains unchanged. In addition, the radiation strength of each unit can be also turned off to provide amplitude control. The main principle for beam scanning is based on the phase compensation to the perturbation units on the surface of the LWA, combined with 1-bit amplitude control to achieve lower sidelobe levels, so the principle is different from that of the existing fixed-frequency beam-scanning LWAs. The entire antenna structure relies on GGW transmission to reduce dielectric loss in millimeter-waveband, and shows good characteristics of scanning angle and realized gain. In the measurement, a high peak gain of 16.8 dBi and a large beam-scanning range over 110° are achieved.

A Quad-Polarization Reconfigurable Fixed-Frequency Beam-Scanning Leaky-Wave Antenna Based on the Holographic Method for Millimeter-Wave Application

A quad-polarization reconfigurable fixed-frequency beam-scanning leaky-wave antenna (LWA) operating at millimeter-wave Ka-band is presented in this article. A low-loss groove gap waveguide (GGW) structure is employed for low-loss transmission and feeding, above which there locates a metal-covered superstrate. Two rows of inclined slots etched on the metal cover in a staggered arrangement operate as the radiated sources. A modified holographic method is presented, and the hologram can be manipulated by switching the states between “ON” and “OFF” of the p-i-n diodes, and hence the fixed-frequency beam-scanning property with polarization agility of four different polarization states can be realized, including horizontal polarization (HP), vertical polarization (VP), left-handed circular polarization (LHCP), and right-handed circular polarization (RHCP). Besides, measured results of the fabricated antenna are given to verify its performance. The measured peak gains at 30 GHz reach 11.3 dBi in the HP state, 13.0 dBi in the VP state, 11.5 dBic in the LHCP state, and 11.8 dBic in the RHCP state, respectively, with a beam-scanning range of 100° (from −50° to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{50}^{\circ }$ </tex-math></inline-formula> ), showing good agreement with the simulated results.

Robust Design of 3D-Printed W-Band Bandpass Filters Using Gap Waveguide Technology

In this paper, a W-band 3D-printed bandpass filter is proposed. The use of higher-order TE10n modes in groove gap waveguide (GGW) technology is evaluated in order to alleviate the manufacturing requirements. In addition to the use of higher-order modes, the coupling between them is analyzed in detail to improve the overall fabrication robustness of the component. This allows the implementation of narrow-band filters operating at millimeter-wave frequency bands (or above), which usually demand complex manufacturing techniques to provide the high accuracy required for this kind of devices. In order to show the applicability of the proposed method, a narrow-band 5th-order Chebyshev bandpass filter centered at 94 GHz, which can be easily fabricated by state-of-the-art stereolithographic (SLA) 3D-printing techniques followed by silver coating, is shown. Excellent measured performance has been obtained.