Xiong Zou

Bio: Xiong Zou is an academic researcher. The author has contributed to research in topics: Return loss & Slot antenna. The author has an hindex of 6, co-authored 7 publications receiving 142 citations.

Y-junction power divider based on substrate integrated waveguide

Abstract: The substrate integrated waveguide (SIW) plays a very important role in millimetre-wave and microwave integrated circuits and systems with low return loss and high Q-factor. Also, the half-mode substrate integrated waveguide (HMSIW) has been developed in recent years. A new Y-junction four-way power divider is proposed by integrating the 90° Y-junction SIW power divider and HMSIW power divider. Simulated and measured results show that the return loss of the input port is below -15 dB over 8.6 to 12.2 GHz and transmissions are about -7.6 dB ± 0.2 dB in the passband. So, it makes the 6 dB power divider used preferably in a broad bandwidth. The new power divider can be produced in batches and can be widely used in millimetre-wave and microwave circuits owing to its simple and novel structure.

SIW-Fed Yagi Antenna and Its Application on Monopulse Antenna

Abstract: Planar Yagi antennas are commonly hard to possess simple structure, high gain, and broad bandwidth at the same time. In this letter, a new substrate integrated waveguide (SIW)-fed Yagi antenna is proposed with nonplanar director element, and it achieves bandwidth of 25.7% and gain of 9.46 dBi at 10.0 GHz. Integrated of an SIW hybrid ring coupler, a Yagi monopulse antenna is designed. Measured gain of the sum pattern is higher than 13 dBi, whereas the maximum null depth of the difference pattern is lower than ${-}$ 20 dB in 9.4–10.05 GHz. This type of monopulse antenna presents an excellent candidate in directional-finding system.

Wideband Hybrid Ring Coupler Based on Half-Mode Substrate Integrated Waveguide

Abstract: A substrate integrated waveguide ring coupler and a half-mode substrate integrated waveguide ring coupler in X-band are designed from the principle of traditional 180 ° hybrid ring coupler. The HMSIW hybrid ring coupler, adopted closed side to closed side designing for connections of HMSIW branches, is proposed for the first time. It has 24.6% bandwidth for the amplitude imbalance of coupling coefficient less than ±0.5 dB and phase differences between outputs are 15.0 ° ~ -5.8 ° and 175.5 ° ~ 189.7 ° for the in-phase and the out-of-phase operations, respectively, which shows much better performance than SIW coupler.

Multimode resonator based on composite right-/left-handed transmission line for UWB bandpass filter application

Abstract: A new multimode resonator MMR using composite right-/left-handed transmission line CRLH TL is proposed and discussed. The CRLH TL structure is constructed by cascading interdigital coupled microstrip line sections on which short-ended stepped impedance stubs are loaded. Dispersion characteristic of the transmission line structure is obtained using the Bloch-Floquet theory. The resonator, which has multiresonances electrical behaviors, is especially suitable in ultrawideband UWB applications. An UWB filter is presented as an illustration. With transmission zeros introduced at upper stopband, the filter has a sharp skirt performance. In addition, rejection level at lower stopband also gets enhanced due to direct current suppression effects of the multimode resonator. The filter prototype is implemented and measured. The measured results validate the theoretical analysis and show that the filter has a sharp skirt and an out-of-band rejection level as good as 38 dB. Meanwhile, return loss is better than 16 dB. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:815-824, 2015.

Design of an X-band symmetrical window bandpass filter based on Substrate Integrated Waveguide

Abstract: Substrate Integrated Waveguide (SIW) is a new kind of microwave transmission structure appeared in recent years. The SIW technique makes it possible that a complete circuit including planar circuitry, transition, and rectangular waveguide are fabricated in a planar form using a standard printed circuit board (PCB). From analysis of the susceptance of symmetrical window and designing process of Chebyshev bandpass filter in rectangular waveguide, an X-band filter based on SIW is designed and fabricated in this article. The simulated results show that the bandwidth of the filter is 5%. The insertion loss is about 1.4 dB, and return loss is about 25 dB at 10 GHz. The measured insertion and return losses are about 2.9 dB and about 13 dB, respectively at mid-band frequency. The filter has a small insert loss and good frequency selective performances from 9.82GHz to 10.20GHz. It is suitable for designing millimeter-wave circuits, and can be produced with batches to be widely used in the microwave systems with the simple structure.

Wideband Substrate-Integrated Waveguide-Fed Endfire Metasurface Antenna Array

Abstract: A vertically polarized substrate-integrated waveguide (SIW)-fed endfire metasurface antenna array is proposed for wideband operation. Each of the metasurfaces consists of $3\times 3$ rectangular patches and is printed on the two surfaces of a single-layered substrate with a thickness of $0.16\lambda _{0}$ (where $\lambda _{0}$ is the wavelength at 32.65 GHz in free space). The antenna is fed at one side of metasurface by an open-end SIW for wideband endfire radiation. The proximity-coupled interdigital strips are introduced between the SIW and metasurface for fault-tolerant coupling. The wideband operating mechanism is revealed by studying the propagation mode and multiple resonant modes of metasurface. To verify the proposed antenna, a $1\times 4$ array is presented with uniform excitation including two SIW Y junctions and an SIW T junction. Moreover, the connected SIW Y junction improved the impedance matching at the low frequencies based on the cavity mode analysis. The proposed design shows that the measured impedance bandwidth (10 dB return loss) is 26.6–38.7 GHz (37%) with the achieved gain of 9.1–13.8 dBi.

A Novel Planar Reconfigurable Monopulse Antenna for Indoor Smart Wireless Access Points’ Application

Abstract: In this paper, a novel planar reconfigurable monopulse antenna with compact size is proposed and studied for indoor smart wireless access points (WAPs) application. Circular polarization is achieved by using a dual-mode substrate integrated waveguide (SIW) slot antenna. Two diagonal ports are individually used to excite the SIW element antenna to achieve a 180° phase-shifting excitation. A reconfigurable $2 \times 2$ prototype is developed with the proposed element antenna, and it uses eight PIN diodes as four switches to implement the reconfiguration. Sum beams, difference beams in azimuth and elevation planes, and bidifference beams are generated. Measurement results verify the designed prototype, showing that the antenna has a null depth of over 30 dB and a peak sum beam gain of 12.29 dBi. The measured 10-dB return loss bandwidths are 5.72–5.96, 5.75–5.95, 5.73–5.97, and 5.76–5.94 GHz for the sum, elevation difference, azimuth difference and bidifference beams, respectively. And their measured 3-dB axial ratio (AR) bandwidths are 5.84–5.88, 5.86–5.90, 5.85–5.9, 5.85–5.9, and 5.84–5.91 GHz. The capability of reconfigurable monopulse beams ensures that the proposed antenna is a good candidate for smart WAP applications.

Millimeterwave and Terahertz Waveguide-Fed Circularly Polarized Antipodal Curvedly Tapered Slot Antennas

Abstract: Antipodal curvedly tapered slot antennas (ACTSAs) with different slot profiles are investigated to achieve the optimum circular polarization performance. The profiles of the tapered slots can be determined by different curves, such as linear, exponential, and logarithmic curves. Therefore, the corresponding waveguide-fed circularly polarized (CP) antipodal linear, exponential, exponential-logarithmic tapered slot antennas (AL-, E-, EL-TSA) are designed, fabricated, and measured at Ka-band for a comprehensive study. The optimized AELTSA provides good impedance matching, gain above 10.3 dBi, sidelobe lower than $-15 {\rm dB}$ , low cross-polarization, and left-hand circularly polarized (LHCP) axial ratio (AR) lower than 3 dB, from 28 to 40 GHz. Moreover, a waveguide-fed LHCP antipodal exponential–exponential tapered slot antenna (AEETSA) is designed at 500 GHz and fabricated by silicon micromachining. The radiation characteristics are examined by measurement results of symmetric beams and ARs lower than 1.5 dB, from 490 to 510 GHz.

Miniaturized Substrate Integrated Waveguide (SIW) Power Dividers

Abstract: In this letter, compact substrate integrated waveguide (SIW) power dividers are presented. Both equal and unequal power divisions are considered. A quarter-wavelength long wedge shape SIW structure is used for the power division. Direct coaxial feed is used for the input port and SIW-to-microstrip transitions are used for the output ports. Four-way equal, unequal and an eight-way equal division power dividers are presented. The four-way and the eight-way power dividers provide −10 dB input matching bandwidth of 39.3% and 13%, respectively, at the design frequency $\text {f}_{0}= 2.4$ GHz. The main advantage of the power dividers is their compact sizes. Including the microstrip to SIW transitions, size is reduced by at least 46% compared to other reported miniaturized SIW power dividers.

Recent Advances in Theory and Applications of Substrate-Integrated Waveguides: A Review

Abstract: The use of substrate integrated waveguides (SIW) for microwave and millimeter wave integrated components has increased dramatically over the last decade. They mimic the performance of conventional metallic waveguides and they are fabricated using printed circuit boards using the top and bottom metallisation with two rows of vias forming the side walls. This creates a low profile, compact, and light weight alternative to conventional metallic waveguides, and they allow a direct interconnection with printed circuit boards and active components. This paper reviews the fundamental theory, documents the research that has been performed over the past decade, and summarises progress up to the recent state-of-the-art including novel SIW structures for passive circuits and antennas as well as new applications for reconfigurable and printed circuits using SIW technology.