Groove Gap Waveguide Technology Research Articles

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.

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.

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.

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.

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.

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.

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.

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.

Development of a compact transverse slot array antenna using corrugation in groove gap waveguide technology

SummaryWe present the proof of concept of a compact slot array antenna with proper side lobe level in groove gap waveguide (GGW) technology. Four transverse slots are etched at the GGW broad wall along with the nulls of standing TE10 wave existing inside the shorted GGW. To decrease the sidelobes and antenna size, corrugations are applied through the wave path inside the GGW. Proper use of corrugations can reduce the wavelength inside the GGW leading to reduction of the distance between adjacent transverse slots, which can help to suppress the grating lobe problem and consequently enhance the radiation efficiency, which is a challenge in transvers slot array antennas. The designed antenna is optimized to achieve maximum gain, lowest grating lobe level, and return loss at 15 GHz using HFSS simulator. The achieved gain is about 13 dBi, and the SLL is better than 15 dB. To confirm the simulation results, the designed antenna was fabricated and tested. Both simulation and measurement results confirm that the grating lobes are well suppressed at the antenna operating frequency.

Fully Metallic Glide-Symmetric Leaky-Wave Antenna at Kₐ-Band With Lens-Augmented Scanning

A fully metallic leaky-wave antenna (LWA) with enhanced scanning rate is presented. The leaky waveguide is implemented in groove gap waveguide technology and is periodically loaded to produce backward radiation. Furthermore, glide-symmetric pins are placed inside the leaky waveguide to increase the dispersion. A parallel-plate waveguide metasurface prism lens is used to disperse the backward radiation and increase the scanning rate of the LWA. The designed antenna can steer the radiation from −26° to 26° from 27 to 35 GHz, and an average total efficiency of 74% is achieved. A prototype of the designed antenna is manufactured, and measurements corroborate the simulated results. The proposed concept is applicable to other frequency-scanning antennas and can be used to increase the scanning rate in radar and imaging systems.

Wideband mm-wave high-gain multibeam antenna array fed by 4 × 4 groove gap waveguide butler matrix with modified crossover

This paper presents a wideband millimeter wave (mm-Wave) high-gain multibeam antenna array fed by Butler Matrix (BM) based on groove gap waveguide (GGW) technology. First, the components of 4 × 4 GGW BM have been designed and analyzed, especially the proposed modified crossover, which greatly improves the performance of BM as feeding network. Then a 2 × 2-element subarray with three layers has been proposed, combined with the 4 × 4 GGW BM to form a 1 × 4 broadside antenna array. Finally, the prototype of high-gain wideband four-beam antenna array has been manufactured and measured. The measured results verify the superior performance of the multibeam antenna array between 26.3-29.7 GHz. The return loss (RL) can reach 15 dB and isolation between ports is also less than 15 dB, and the measured maximum gain of radiation patterns and the maximum radiation efficiency can also reach 19.05 dBi and 86.8%, respectively. The measured results have a good agreement with the simulated results.

Low-Loss Mechanically Tunable Resonator and Phase Shifters in Groove Gap Waveguide Technology

This research is focused on the design and realization of high-performance high-power variable phase shifters in groove gap waveguide technology. Specifically, it is shown that the unique characteristic of groove gap waveguides, which is its proper operation without the need for electrical connection between the top and bottom sections of the waveguide, can be used to design mechanically tunable devices. Using the proposed method, a mechanically tunable cavity resonator and phase shifters with a wide range of achievable phase shifts are presented. To validate the concept, a phase shifter with 540 degrees relative phase shift at 15 GHz is designed, fabricated, and measured. Moreover, a multi-layer version of the proposed phase shifter with stationary feed ports and improved performance is presented.

High Dynamic Range Microwave Displacement and Rotation Sensors Based on the Phase of Transmission in Groove Gap Waveguide Technology

This research is focused on the design and realization of displacement sensors in gap waveguide technology. It is shown that with a small but fundamental change in the structure of a conventional gap waveguide, a linear displacement can be sensed. To this end, a unique feature of gap waveguides, i.e. the fact that no electrical connection between the top and bottom parts of the gap waveguide is required, is used. It is further shown that the concept can be also used for the development of rotation sensors. To validate the proposed concept linear and angular displacement sensors are designed and simulated. A prototype of the proposed linear displacement sensor is fabricated for demonstration. Agreement between the computed and measured results validates the concept.

Wideband Rotary Joint Based on Gap Waveguide Technology

This article presents a wideband design of a rotary joint based on groove gap waveguide technology. The proposed design includes two coax-to-groove gap waveguide (GGW) transitions, connected together in a back-to-back arrangement. As the gap waveguide structure does not require electrical connections between different parts, the rotor part is placed on top of the stator with an air gap distance while the wave leakage is suppressed. Therefore, the rotating choke, which is a critical and bulky part in the previous designs, is eliminated. By introducing some matching posts in the structure, a wideband design is achieved with 55% bandwidth covering from 11 to 19.5 GHz, where the insertion loss is lower than 0.28 dB. Some parameter sweeps are presented to investigate the effect of the rotor displacement during rotation. A prototype of the proposed rotary joint was fabricated using CNC milling for verification of the design. The measured results agree well with the simulated ones and prove the excellent performance of the proposed rotary joint.

Ka-band planar slotted waveguide array based on groove gap waveguide technology with a glide-symmetric holey metasurface

The design of a planar slot array in groove gap waveguide technology implemented by glide-symmetric holes as Electromagnetic Band Gap structure is here presented. Despite the advantages of using holes instead of pins in terms of manufacturing simplicity and cost,the larger size of the holes compared to pins needs to be considered when designing slot arrays without grating lobes. A 1 to 4 corporate feed network is designed using this technology as well. Corrugations are included to further reduce the grating lobes. Experimental results support the viability of the proposed concept for designing glide-symmetric planar arrays of any size.

Implementation of tunable resonators in planar groove gap waveguide technology

Abstract We present a tunable planar groove gap waveguide (PGGWG) resonant cavity at Ka-band. The cavity demonstrates varactor loading and biasing without bridging wires or annular rings, as commonly is required in conventional substrate-integrated waveguide (SIW) resonant cavities. A detailed co-simulation strategy is also presented, with indicative parametric tuning data. Measured results indicate a 4.48% continuous frequency tuning range of 32.52–33.98 GHz and a Qu tuning range of 63–85, corresponding to the DC bias voltages of 0–16 V. Discrepancies between simulated and measured results are analyzed, and traced to process variation in the multi-layer printed circuit board stack, as well as unaccounted varactor parasitics and surface roughness.

Array of stacked leaky-wave antennas in groove gap waveguide technology

The design of an array of stacked leaky-wave antennas in groove gap waveguide technology is presented in this work. The proposed array is formed by simply stacking a number of leaky-wave antennas one on top of the other and feeding all of them with uniform amplitude and phase. The inter-element distance is studied in order to avoid grating lobes and to maximize the directivity. A feeding network based on vertical coupling is designed, where the input port feeds the bottom element, and then the energy is equally coupled to the other elements. To obtain maximum directivity the phase is corrected at each element separately. The central frequency of the proposed design is 28 GHz. With this technique of stacking the elements a pencil beam is achieved, i.e. the radiated energy is focalized in the two main planes. The designed array with four elements achieves an enhancement of + 5 dB, reaching 24.5 dBi of directivity in comparison to 19.6 dBi of directivity of the single leaky-wave antenna made in this technology. A prototype is manufactured and measured and its results are presented and compared with the simulations.

Technology Assessment of Aperture Coupled Slot Antenna Array in Groove Gapwaveguide for 5G Millimeter Wave Applications

A compact triple-layer series fed slot unit array using Groove Gap Waveguide (GGW) technology for 5G millimeter-wave applications is presented in this paper. The design employed a two-step coupling mechanism for the radiating slots. The aperture coupling design when combined with the groove gapWaveguide (GGW) technology allows achieving three different goals: First, a reduction of the array size in the transversal direction, so more unit arrays can be added without grating lobes. Secondly, low insertion losses with high radiation efficiency. And third, a reduction of the manufacturing complexity with good stability against fabrication tolerances of up to 0.1 mm, making the design feasible to be massively deployed. The antenna was fabricated and measured showing good agreement with the numerical simulation results, the antenna provides a peak realized gain of 12.15dB at the central frequency of operation and a fractional bandwidth (FBW) of 9%.

A Simple Asymmetric Orthomode Transducer Based on Groove Gap Waveguide

The groove gap waveguide (GGWG) technology is used to design a simple asymmetric orthomode transducer (OMT) at the Ka -band in this letter. The OMT consists of two metal layers which do not need electrical contact due to the property of the gap waveguide technology. The vertical polarization (VP) is directly fed to a standard rectangular waveguide port from the main arm of a square waveguide, while the horizontal polarization (HP) is fed to the side arm by an H-bend. No septum or iris is needed, which contributes to a simple structure. The OMT has been manufactured and measured using a back-to-back setup. A high isolation of over 40 dB is achieved within the working band from 26.1 to 29.3 GHz. The reflection coefficient is below −11.4 and −17.7 dB for the HP and VP, respectively. The higher return loss of the HP is caused mainly by the manufacturing errors. Nevertheless, the insertion loss for both polarizations is below 0.25 dB for a single OMT.