Miniaturized high-gain synthetic rectangular waveguide antenna of near-omnidirectional radiation pattern

A miniaturized synthetic dielectric-filled rectangular waveguide antenna of near-omnidirectional radiation pattern is presented. The main body of the antenna is the synthetic rectangular waveguide (SRW), consisting of two-dimensional (2D) photonic bandgap (PBG) arrays at both top and bottom surfaces of the SRW. The waveguide antenna with size of 71.0 mm by 10.5 mm, consisting of 4 slots (each 7.0 mm by 0.4 mm) in the broadside wall, is built by conventional FR4 (epsilon(r) = 4.1) processes. Between 4.78 GHz and 5.65 GHz, the measured input reflection coefficient including the effects of the connector and microstrip-to-waveguide transition is kept below -10dB. The proposed synthetic waveguide antenna shows the maximum antenna gain of 4.28 dBi and 3dB beamwidth of 130degrees at 9.5degrees from the broadside of the antenna at 5.25 GHz, demonstrating a great potential for portable communication devices.