Printed Gap Waveguide Technology Research Articles

2 × 2 Slot Spiral Cavity-Backed Antenna Array Fed by Printed Gap Waveguide

A wideband circularly polarized slot spiral antenna array excited by a printed gap waveguide (PGW) feeding network is presented in this paper. The equiangular slot spiral is etched on the top wall of the substrate integrated cavity (SIC) in which TE120 mode is excited. Due to excitation of this mode, electric field distribution in two halves of the substrate integrated cavity is the same in magnitude and 180° out of phase. Therefore, the slot spirals are fed differentially by this cavity and become independent of the complex vertical balun structures. The sequential feeding is implemented by PGW technology, which results in high efficiency of the array structure. Moreover, by employing SIC and PGW technologies, this antenna is compatible with low cost printed circuit board (PCB) technology. A prototype of the proposed antenna was fabricated and measured to evaluate the antenna performance. The fabricated antenna array shows the -10 dB impedance bandwidth of 23.7% and the 3 dB AR of 22.5% with the measured RHCP gain of 12.3 dBic.

Self-Packaged, Low-Loss, Planar Bandpass Filters for Millimeter-Wave Application Based on Printed Gap Waveguide Technology

A new concept of printed planar technology is introduced for the realization of low-loss bandpass filters in millimeter band. The new technology is self-packaged, and the insertion loss shows meaningful improvement compared to microstrip (MS) filters. The designs are based on the ridge gap waveguide (RGW), which is composed of printed parallel-plate waveguide surrounded by beds of mushrooms that suppress the signal around the waveguide. Several examples are designed, optimized, and measured. All-pole bandpass filters and filters with finite transmission zeros are proposed and studied. The performance of the proposed designs is compared to MS filters with different packaging options. In addition, an efficient transition from MS to printed RGW is designed and used in the circuits. The proposed circuits are low-cost and realizable using conventional printed circuit board technology. Measured results show good agreement with the analyses.

Fully Printed Gap Waveguide With Facilitated Design Properties

An improved concept is introduced to facilitate the design of low-loss planar circuits using printed gap waveguide technology. The method is based on using separate layers to realize the EBG cells and the lines. As a result, the operating bandwidth of the waveguide is increased compared to the printed ridge gap waveguide. Also, the design process is simplified regarding the placement of the cells around the resonators and lines. Measured results of a line with two 90° bends and a quadruplet bandpass filter are presented that prove the concept. A transition to microstrip line is used in order to acquire the ability to use test probe fixture.