Wideband Low-Sidelobe Slot Array Antenna With Compact Tapering Feeding Network for E-Band Wireless Communications

Abstract

In this work, a wideband low-sidelobe slot array antenna for wireless communication system at E-band is presented. The slots are excited by a parallel feeding network where the Taylor distribution is applied. Two types of wideband unequal power divider with compact structures are designed for various output ratios to fit the limited feeding network space. One is integrated vertically inside a 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 1 elements subarray using a set of pins with asymmetrical offset. The other type is designed inside an E-plane T-junction with unbalance impedance at two output ports. To avoid main lobe tilt and asymmetrical radiation patterns, the feeding network is designed to be biaxially symmetrical, and the feed port is placed in the center of the back. A prototype is fabricated with brass and measured in an anechoic chamber. It achieves a peak gain of 25.8 dBi and a fractional impedance bandwidth of 19.2% with the reflection coefficient below −10 dB. The measured radiation patterns agree with the simulated patterns very well, and the sidelobe level (SLL) is lower than −21 dB.