Fixed-Frequency Beam Steering Leaky-Wave Antenna With Integrated 2-Bit Phase Shifters

In this communication, a reconfigurable 2-bit leaky-wave antenna (LWA) is proposed for low-cost fixed-frequency beam-steering applications. The proposed antenna consists of a microstrip transmission line loaded with several branches, a series of 2-bit phase shifters, and a
$1\times 8$
patch array. Each phase shifter is built by selecting the feed directions on the branch and introducing slot perturbation on the patch, thus no phase delay line is used. Only three p-i-n diodes are needed to control the 0°, 90°, 180°, and 270° states of the element. The reference phase
$\varphi _{0}$
, namely the phase of the first element, is utilized to enhance the peak gain of the array. The stopband effect of broadside beam is eliminated due to the perturbation on the patches. The prototype is tested at 3.6 GHz. The measured peak gain is 13.54 dBi, and the main beam can steer from
$- \mathrm{48}^{\circ }$
to
$+ \mathrm{46}^{\circ }$
.