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Author

Zhe Chen

Bio: Zhe Chen is an academic researcher from Yunnan University. The author has contributed to research in topics: Terahertz radiation & Antenna measurement. The author has an hindex of 1, co-authored 3 publications receiving 7 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, a 3-dB waveguide hybrid coupler with three coupling branches with a circular cutout at the top and bottom on both sides of the main branch is proposed.
Abstract: This letter presents our investigation into a 3-dB waveguide hybrid coupler of a novel structure in the submillimeter frequency band. The proposed coupler has only three coupling branches with a circular cutout at the top and the bottom on both sides of the main branch and is of compact size. The simulation shows that the proposed design has eased the machining difficulty by providing more tolerance to fabrication errors. The simulation also shows that the amplitude imbalance of the proposed hybrid branch is 25% less than that of the traditional three-branch hybrid structure. The proposed coupler structure is verified in experiment through measuring a fabricated 90° waveguide coupler at a center frequency of 195 GHz with approximately 13% bandwidth where the amplitude imbalance is less than 0.3 dB. The simulated and measured S-parameters have shown that the amplitude and phase imbalances are within 0.3 dB and 4°, respectively, with an isolation and return loss of 17 dB.

18 citations

DOI
09 Dec 2022
TL;DR: In this paper , a metamaterial bandpass frequency selective surface (FSS) in the terahertz (THz) range is realized by the cascade of two similar double-ring-like structures with four transmission zeros on either side of its passband to obtain a quasi-elliptical filter response.
Abstract: A metamaterial bandpass frequency selective surface (FSS) in the terahertz (THz) range is realized by the cascade of two similar double-ring-like structures with four transmission zeros on either side of its passband to obtain a quasi-elliptical filter response. The proposed FSS is analyzed by the equivalent circuit model, and the simulation results show that the structure has a 3dB bandwidth of 0.06THz at the center frequency of 0.43THz, and has stable bandpass characteristics in the range of incident angle $0-40^{0}$. The FSS has a simple structure, good rectangular coefficient, great out-of-band rejection below 30dB and rectangular coefficients, and can play an important role in terahertz imaging, communication and other fields.
Journal ArticleDOI
01 May 2023-Sensors
TL;DR: In this article , a Yagi-Uda antenna with stable gain by near-zero-index metamaterial (NZIM) has been proposed for vehicular 5G communication, which consists of magneto-electric dipole structure and coaxial feed patch antenna.
Abstract: In this paper, a stereoscopic ultra-wideband (UWB) Yagi–Uda (SUY) antenna with stable gain by near-zero-index metamaterial (NZIM) has been proposed for vehicular 5G communication. The proposed antenna consists of magneto-electric (ME) dipole structure and coaxial feed patch antenna. The combination of patch antenna and ME structure allows the proposed antenna can work as a Yagi–Uda antenna, which enhances its gain and bandwidth. NZIM removes a pair of C-notches on the surface of the ME structure to make it absorb energy, which results in two radiation nulls on both sides of the gain passband. At the same time, the bandwidth can be enhanced effectively. In order to further improve the stable gain, impedance matching is achieved by removing the patch diagonally; thus, it is able to tune the antenna gain of the suppression boundary and open the possibility to reach the most important characteristic: a very stable gain in a wide frequency range. The SUY antenna is fabricated and measured, which has a measured −10 dBi impedance bandwidth of approximately 40% (3.5–5.5 GHz). Within it, the peak gain of the antenna reaches 8.5 dBi, and the flat in-band gain has a ripple lower than 0.5 dBi.
DOI
09 Dec 2022
TL;DR: In this paper , a dual-band bandpass filter with center frequencies of 0.85 and 1.65 GHz was proposed. But the authors only considered the first passband and the second passband.
Abstract: This paper presents a dual-band bandpass filter based on $\lambda$/4 stepped impedance resonator (SIR), and the principle is introduced in detail. Each passband frequency and bandwidth of the filter can be designed flexibly. In order to verify the effectiveness of this design, a dual-band bandpass filter with center frequencies of 0.85 and 1.65 GHz is designed. The simulation results show that The insertion loss at the center frequency of 0.85 GHz is 0.43 dB and the return loss is 34.2 dB,-3dB fractional bandwidth (FBW) of 16.4 %. The insertion loss at the center frequency of 1.65 GHz is 0.6 dB and the return loss is about 30. SdB, -3dB FBW of 9.1 %. Due to the use of tap feeding and hybrid coupling, the coupling phase changes, and two transmission zeros (TZs) are generated on both sides of the second passband, which greatly increases the out-of-band suppression performance of the filter.
Proceedings ArticleDOI
01 Sep 2018
TL;DR: In this article, a 590-650GHz terahertz sub-harmonic mixer using wide pads was presented to reduce the mismatch caused by manual assembly of the flip chip diode.
Abstract: In this paper, a 590-650GHz terahertz sub-harmonic mixer using wide pads was presented to reduce the mismatch caused by manual assembly of the flip chip diode. In order to improve design accuracy, the exact 3D model of the planar Schottky diode was built. And the influence of the silver glue metal layer formed in manual assembly on the performance was study. The RF/LO matching networks were designed with consideration of minimizing the influence of manual assembly. The simulation exhibits that the conversion loss of the mixer is less than 10dB range from 590GHz to 650GHz when the LO pumped power is 3dBm, and the best performance of conversion loss is 8dB at 620GHz.

Cited by
More filters
Journal ArticleDOI
TL;DR: In this article, a 400 GHz broadband multi-branch waveguide hybrid coupler is designed, but it is very difficult to fabricate and it is also measured in order to release the processing difficulty.
Abstract: Terahertz technology is a hotspot in the current academic research. In this study, a 400 GHz broadband multi-branch waveguide hybrid coupler is designed, but it is very difficult to fabricate. In order to release the processing difficulty, a modified five-branch hybrid coupler has also been designed, fabricated and measured. The hybrid coupler consists of five modified branches and has been optimised to a great performance, which increases the operation bandwidth. Compared to the traditional five-branch hybrid coupler design, this structure has a wider operation bandwidth and the bandwidth is almost the same as traditional seven-branch hybrid coupler. Based on this model, the performance of the coupler is optimised by HFSS software. The measurement results show good performance that >18 dB return loss (S 11 ) and isolation (S 23 ), 90° ± 2° phase difference and 0.3 dB amplitude imbalance are obtained in the frequency range of 380-460 GHz, agreeing well with the simulation results.

50 citations

Journal ArticleDOI
TL;DR: In this paper, a 3-dB waveguide hybrid coupler with circular cutouts at the top and bottom on both sides instead of the traditional rectangle branch was designed and analyzed for submillimeter and terahertz bands.
Abstract: This paper presents a mechanical reliability study of 3-dB waveguide hybrid couplers in submillimeter and terahertz bands. To show the necessity of improving the mechanical properties of the coupler’s branch in submillimeter and terahertz bands, a comprehensive study regarding the displacement of hybrid branch variation with varying width-length ratio and height-length ratio has been completed. In addition, a modified 3-dB waveguide hybrid coupler is designed and presented. Compared with the traditional branch structure, the proposed hybrid consists of a modified middle branch with circular cutouts at the top and bottom on both sides instead of the traditional rectangle branch, which increases the branch size and improves its mechanical reliability while achieving the same performance. Simulation results show that the deformation of the modified hybrid branch is 22% less than those of other traditional structure designs under the same stress. In practice, a vibration experiment is set up to verify the mechanical reliability of hybrid couplers. Measurement results show that the experiment deteriorates the coupling performance. Experimental results verify that the performance of the novel structure coupler is better than that of a traditional structure branch hybrid coupler under the same electrical properties.

31 citations

Journal ArticleDOI
TL;DR: In this paper , a 220 GHz multi-circuit inte-grated front end based on solid-state circuits is presented. But the size of the proposed multi circuit integrated front-end block is 25 mm × 20 mm ×20 mm, ten times smaller than the cascading transceiver.
Abstract: This paper presents the research on a 220 GHz multi circuit inte-grated front end based on solid-state circuits. This integrated front end integrates a 220 GHz subharmonic mixer, a 110 GHz tripler, a 110 GHz 8 dB hybrid coupler and a 220 GHz waveguide bandpass filter (BPF) in one single block. Compared to the traditional transceivers which usually use cascade connection of the independent mixers and multipliers, the size of the proposed multi circuit integrated front-end block is 25 mm × 20 mm × 20 mm, ten times smaller than the cascading transceiver. In order to check the tripler’s output power, a modified compact 110 GHz 8 dB hybrid coupler is set between mixer and tripler. Due to the characteristics of the hybrid coupler, the deterioration of cascading transceiver’s performance caused by mismatch has also been improved. In addition, to achieve single sideband (SSB) communication, a 220 GHz BPF with high selectivity is integrated in the circuit. The measured conversion loss of the fabricated multi circuit integrated front end is less than 11 dB, where the LO and RF frequency are 37 and 210−220 GHz. Based on this front-end, a 220 GHz high speed communication system has been setup and it can achieve 10 Gbps data transmission using 16QAM modulation.

28 citations

Journal ArticleDOI
TL;DR: In this article , a novel ultrawideband branch waveguide coupler with low amplitude imbalance was proposed, which is based on a new waveguide obtained by symmetrically increasing the waveguide width.
Abstract: In this article, we present a novel ultrawideband branch waveguide coupler (BWC) with low amplitude imbalance. This novel design is based on a new structure of branch waveguide obtained by symmetrically increasing the waveguide width. The coupling degree can be independently controlled by the height and width of the new branch waveguide, which significantly increases the design flexibility. In addition, this structure can produce a transmission zero (TZ), and a concept to improve the fractional bandwidth of the BWC with out-of-band TZ is proposed. Based on the analysis, the design guidelines for the novel BWC are provided. For a given center frequency, an n-branch novel BWC can be easily designed. Moreover, because of the larger branch waveguide height, this novel design has greatly eased the machining difficulty. Finally, to verify the design concept, a $W$ -band eight-branch prototype is processed and measured. In full $W$ -band, the amplitude imbalance is less than 0.52 dB, the phase imbalance is less than 2.5°, the return loss (RL) is greater than 21.4 dB, and the isolation is greater than 20.5 dB. The simulation and experimental results are in good agreement.

27 citations

Journal ArticleDOI
TL;DR: In this article, a ring-shaped $E$ -plane filtering coupler is presented for 150 GHz with high performance, which is based on cavity resonators, and the measured response of the coupler has an excellent agreement with the simulation, with a low amplitude imbalance of 0.31 dB, insertion loss, and over 20-dB return loss and isolation.
Abstract: This letter presents a ring-shaped $E$ -plane filtering coupler working at 150 GHz with high performance. The coupler is based on cavity resonators. Unlike the conventional ones, the four resonators in this coupler are all bent along their length direction and connected end to end, forming a closed circle. By adjusting the radius of the circle, three of the resonators work on TE101 mode while the other is on TE102 mode. The coupler can be split through $E$ -plane and the measured response of the coupler has an excellent agreement with the simulation, with a low amplitude imbalance of 0.31 dB, insertion loss of 0.12–0.46 dB, and over 20-dB return loss and isolation.

9 citations