A Continuously Tunable Phase Shifter Using Surface Waves

Abstract

In this paper we present the theory, design, and implementation of a continuously tunable phase shifter using a surface-wave structure. The surface-wave travels on a reconfigurable impedance surface which is implemented by arranging dipoles on a single-layer PCB where a varactor is placed in the gap in the middle of each dipole. The proposed phase shifter operates at X-band from 8.5 to 10 GHz and it can provide 464 o phase shift with a figure of merit of 110 o /dB at 9.16 GHz. In the designed phase shifter, the varactor loss is less than all other loss mechanisms which makes it possible to achieve a high figure of merit at a high frequency range. The proposed phase shifter can be used in the design of phased arrays that require a high radiation efficiency at a relatively high frequency compared to the self-resonance frequency of the tunable electronic components.

Slotted Waveguide Frequency-Scanned Slow-Wave Antenna With Reduced Sensitivity of the Closed Stopband at Millimeter-Wave Frequencies

“…Electrical beam-steerable antennas can be classified into fixed-frequency beam-steerable antennas and frequency-scanned antennas. Due to the considerable drop in the efficiency of tunable electronic components at millimeter-wave frequencies, frequency-scanned antennas can provide better efficiencies at this frequency range, especially if a long electrical length is needed for a small half-power beamwidth (HPBW) and a large gain [8]- [10]. Moreover, at millimeter-wave frequencies, the use of metallic waveguides is appealing due to their reduced losses and the high cost of low-loss dielectric substrates.…”