6-18GHz Phase-shifter; GaAs Monolithic Microwave IC. The CHP4511 is a 4-bit digital phase shifter with an output single pole double through (SPDT) switch. It is designed for 6 to 18GHz frequency range applications. The backside of the chip is both RF and DC grounded. The circuit is manufactured with a Power PHEMT process, 0.25µm gate length, via holes through the substrate, air bridges and electron beam gate lithography. It is available in chip form.