Wave-front adaptive control structure (WACS) for quasi-optical power amplifiers in Intelligent RF front-ends

Tunable electromagnetic crystal (EMXT) surfaces are used as rectangular waveguide sidewalls to provide uniform excitation for quasi-optical power amplifiers. InP hetero-barrier varactors are monolithically integrated into periodic metal-dielectric structures to realize a reconfigurable EMXT surface that has a tunable resonance frequency from 30 to 45 GHz. Real-time reconfigurable (30 - 40 GHz) and low-loss quasi-TEM wave-front control with only 2-mm long EMXT waveguide section is demonstrated. Experimental results are in good agreement with design simulations. Such waveguides can be readily integrated into an intelligent RF front-end with self-assessment and self-adjustment capabilities.