Omnidirectional Horizontally Polarized Magnetic Dipole Array Facilitated by Folded TE0.5,0 Mode Waveguide

Abstract

An omnidirectional horizontally polarized (OHP) magnetic dipole array is reported that achieves a high directivity and has a simple configuration. This OHP array is facilitated by a partially folded $TE_{0.5,0}$ mode rectangular waveguide. A set of folded sections along the waveguide realize collinear and in-phase magnetic dipole radiators thanks to the effective cancellation of the out-of-phase electric fields in them. The entire waveguide is excited by a microstrip feedline via a shorting pin in the middle. A design model has been optimized for the 2.5 GHz WLAN band and achieves excellent radiation performance. The simulated -10dB impedance bandwidth covers 190 MHz (7.8%) from 2.33 to 2.52 GHz. The realized gain values are stable across the entire bandwidth with a 8.7 dBi peak value. Good omnidirectional radiation patterns are also observed with the out-of-roundness value less than 3 dB. The presented OHP magnetic dipole array is an ideal candidate for point-to-multipoint communication or wireless power transfer applications.