Fixed-Frequency Beam-Steering Using Slotted Waveguide With Tunable Impedance Walls

In this paper, we describe the development of a new beam-steerable antenna array using a reconfigurable waveguide with tunable impedance side walls. The array has 36 radiating elements placed on the top wall of the waveguide and a common biasing voltage for tuning the impedance walls. The antenna operates at 9.3 GHz and its beam can be steered from 22° to 65° by changing the bias voltage from 16 to 7 volts. The gain of the antenna remains within the 3 dB limit of the maximum gain of 11.8 dB throughout the steering range. The effective radiating length of the antenna is
$13\lambda $
and its half-power beamwidth is 5°. For this frequency range and electrical length, this antenna has a high radiation efficiency. This is due to the phase-shifting mechanism used which results in the varactor loss being less than all other sources of loss throughout most of the steering range. This makes the antenna suitable for applications where the varactors should operate at high frequencies with relatively low quality factors.