Sai-Wai Wong

In this paper, a dual-mode dual-band filter based on half-mode substrate integrated waveguide (HMSIW) is presented. The proposed filter has the capability to tune the two pass-bands independently. The proposed filter consists of two HMSIW resonators coupled through a pair of E-shaped coupling slots. Two resonating modes (TE101 and TE102) are excited in each resonator. A varactor diode is used in the proposed filter for tuning purpose. The varactor diode is placed in the structure in such a way that both bands can be tuned independently. The lower passband can be tuned from 3.26 to 3.47 GHz with insertion loss of 0.2-2.9 dB. The higher passband can be tuned from 5.47 to 6.13 GHz with low insertion loss of 0.1-2.1 dB. The presented results show the flexibility of the filter to achieve desired responses and its suitability for integration with any tunable planar structure. A good agreement between the simulated and measured results is observed.

16 September 2019 in IEEE Transactions on Antennas and Propagation

Journal Article

Wideband High-Efficiency Circularly Polarized SIW-Fed S-Dipole Array for Millimeter-Wave Applications

A wideband high-efficiency millimeter-wave (mm-wave) circularly polarized (CP) array which is constituted by novel planar SIW-fed S-dipoles is presented in this paper. The proposed mm-wave CP S-dipole consists of two rotational symmetric curved arms and is fed differentially through aperture coupling, which features simple configu-ration and excellent performance. Detailed analysis is given to explain the operating principles of this element. It is noted that superior element performance including a wide impedance bandwidth of 43%, a wide 3-dB axial ratio (AR) bandwidth of 36% and 1-dB gain bandwidth of 38% is achieved by the planar SIW-fed S-dipole. By feeding 64 in-phase S-dipole elements through a full-corporate SIW feeding network, a planar wideband highly efficient mm-wave 8 × 8 CP array is realized. To verify the design concept, a prototype operating at Ka-band is fabricated and measured. Measurement results indicate that the proposed array achieves a wide overlapped bandwidth of 27.6%, a high antenna gain of 25.2 dBic and a high aperture efficiency of 89.9%. Attributed to the planar and robust array structure as well as its excellent performance, the presented array is a good candidate for various mm-wave applications.

14 November 2023 in IEEE Transactions on Antennas and Propagation

Journal Article

Hybrid Method of Artificial Neural Network and Simulated Annealing Algorithm for Optimizing Wideband Patch Antennas

Jinhua Huang

In order to design the wideband patch antenna, a hybrid method based on the artificial neural network (ANN) and the simulated annealing (SA) algorithm is proposed in this paper. The ANN is employed to describe the nonlinear relationship between the geometric parameters and the S-parameters of the antenna. The ANN is trained by the dataset got by the High Frequency Structure Simulator (HFSS). More importantly, the dataset is divided into three groups according to their own characteristics so that the ANN can be trained faster and better. The SA is employed to broaden the bandwidth of the patch antenna with the required center frequency. Then three wideband patch antennas with different center frequencies are designed to demonstrate the feasibility of the proposed method. Several slots are added to the patch to achieve the wide bandwidth. The results prove that the proposed method can obtain the wideband patch antenna quickly and efficiently.

15 September 2021 in IEEE Transactions on Antennas and Propagation

Journal Article

Multifunctional Orbital Angular Momentum Generator With High-Gain Low-Profile Broadband and Programmable Characteristics

Transmissive and reflective metasurfaces have been extensively studied for generating an orbital angular momentum (OAM)-carrying beam. However, the existing OAM generators suffer from feed blockage, large profile, OAM mode nonreconfigurable, and narrowband. An OAM generator that integrates multiple functions into a single module is in high demand in OAM-based applications. In this study, we proposed an OAM generator based on a folded reflectarray with high-gain low-profile broadband and programmable characteristics. The proposed multifunctional OAM generator, comprising half the volume of the normal OAM metasurfaces, can generate a high-gain $l=0$ , $l=+1$ , and $l=+2$ OAM-mode-reconfigurable beams with high mode purity over the frequency range of 9.5–10.5 GHz. The proposed OAM generator-integrated multiple functions have potential applications in OAM-based wireless communications and radar detection.

15 June 2018 in IEEE Transactions on Circuits and Systems I: Regular Papers

Journal Article

Miniaturized Resonator and Bandpass Filter for Silicon-Based Monolithic Microwave and Millimeter-Wave Integrated Circuits

24 June 2021 in IEEE Antennas and Wireless Propagation Letters

Journal Article

A Planar Absorptive-Branch-Loaded Quasi-Yagi Antenna With Filtering Capability and Flat Gain

Fei Fan

A planar quasi-Yagi antenna with cointegrated filtering functionality and flat in-band gain is reported. It exploits complementary-diplexer-based reflectionless-filtering techniques through the inclusion of an absorptive branch to realize the codesigned filtering functionality. This absorptive branch consists of a second-order bandstop-filter (BSF) unit loaded by a grounded resistor that is connected in parallel with the initial planar quasi-Yagi antenna. By designing the reflection coefficients of the basic antenna and the absorptive branch to be nearly complementary in frequency, the out-of-band RF power not radiated by the antenna is transmitted by the BSF to its loading resistor that dissipates it. In this manner, a quasi-absorptive filtering action is added to the antenna. Moreover, whereas the out-of-band radiation efficiency of the antenna is highly suppressed, its in-band behavior is kept as the in-band RF power is not transmitted by the BSF but radiated by the antenna as usual. For the experimental-validation purposes, a microstrip antenna prototype is developed and measured. Flat in-band gain with a ripple lower than 1 dB within the operational range of the antenna (2.6-3.06 GHz) is obtained as an added merit.

About Me

Sai-Wai Wong (S’06-M’09-SM'14) received his B.S degree in electronic engineering from the Hong Kong University of Science and Technology, Hong Kong, in 2003, and his M.Sc. and Ph.D. degrees in communication engineering from the Nanyang Technological University, Singapore, in 2006 and 2009, respectively. From Jul. 2003 to Jul. 2005, he was an Electronic Engineer and lead an electronic engineering department in China with two Hong Kong manufacturing companies. From May 2009 to Oct. 2010, he was a Research Fellow with the ASTAR Institute of Infocomm Research, Singapore. In 2010, he became an Associate Professor, and later became a Full Professor in the School of Electronics and Information Engineering, South China University of Technology, Guangzhou, China. Since 2017, he has been a Full Professor with the College of Electronics and Information Engineering, Shenzhen University, Shenzhen, China. His current research interests include RF/microwave circuits and antenna design. So for, he has authored or co-authored more than 200 articles in international journals and conference proceedings. He was a recipient of the New Century Excellent Talents in University Award by the Ministry of Education of China in 2013 and the Shenzhen Overseas High-Caliber Personnel Level C award in 2018.

Sai-Wai Wong

Sai-Wai Wong

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