Dual-Linearly-Polarized Planar Liquid-Crystal-Based Phased Array in $Ka$-Band

This paper presents a compact millimeter-wave dual-linearly-polarized (dual-LP) liquid crystal phased array (LCPA). The LCPA is composed of a number of phase-shifting subarrays which contain eight dual-LP elements and two liquid crystal phase shifters (LCPSs). The LCPS utilizes a loaded differential line structure and can provide continuously tunable transmission phase of 333°. For verification, a prototype of the LCPA is fabricated, experimentally realizing one dimensional dual-LP beam scanning from$+40^{\circ}$to$-40^{\circ}$. Within the operating frequency range of 26 to 32 GHz, the reflection coefficients of two ports are below -10 dB and the port isolation is over 25 dB. The LCPA can achieve a peak gain of$\text{1 5. 9 4 ~ d B i}$and$\text{1 6. 5 4 ~ d B i}$for two orthogonal polarizations, where the scanning loss is under 2.5 dB. The proposed dual-LP LCPA offers an alternative low-cost, high-degrees-of-freedom solution to phased arrays, which can be a potential candidate for millimeter-wave communications.