https://ieeexplore.ieee.org/document/10058704  

The phase-shifting element is a via-pad-slot (VPS) structure using a half-mode substrate-integrated waveguide (HMSIW).

Phase shift is achieved when a VSP structure is covered by liquid metal (LM) running in microfluidic channels on the substrate surface.

X-Band (8 GHz to 14 GHz)

Phase shift is determined by the number of covered VPS structures. The device is linear, self-compensating and almost dispersionless. Insertion loss is low as the internal substrate structure is not disturbed.

Modulators, demodulators, phased antenna arrays.

Phase shift from 0° to 180° Insertion Loss is 1.1dB ±0.1 dB at 11.5 GHz Phase deviation is ±2° (10-12.5 GHz)