Two-Way Tunable Phase Shifter With Arbitrary Phase Shift Ratio at Two Different Frequencies

This article presents a new class of tunable passive two-way phase shifters, which can provide an arbitrary phase shift ratio at two different transmit and receive frequencies ( fT and fR) simultaneously. The proposed phase shifter uses one control element to control both paths. This architecture consists of two transmit and receive paths and a high dielectric constant slab over the paths. By properly setting the length ratio between transmit and receive lines under the dielectric slab, the proposed phase shifters can realize any arbitrary phase shift ratio. For fast and accurate modeling of the proposed phase shifter, a simple Transmission Line (TL) circuit model is presented in this article and verified by full-wave simulations and measurement. The model can be used for calculating the reflection coefficient and phase shift. In order to prove the concept, two phase shifters, one with equal phase shift (ΦT/ΦR = 1) and the other with the phase shift is equal to the ratio transmit frequency and receive frequency (ΦT/ΦR = fT/fR), are designed, fabricated, and measured. All results show very good agreement between the proposed TL model, the full-wave solver, and measurement results. This type of phase shifter can be used for many beamforming antenna systems, such as interleaved arrays, full-duplex arrays, and multiband arrays.