Conformal Ink-Jet Printed $C$-Band Phased-Array Antenna Incorporating Carbon Nanotube Field-Effect Transistor Based Reconfigurable True-Time Delay Lines

We present a conformal ink-jet printed 2-bit four-element phased-array antenna (PAA) without any lithography process. Passive and active components, such as microstrip transmission lines, phase shifters, and RF power distribution networks are all developed adopting a room-temperature printing process. The PAA working at 5.2 GHz is printed on flexible DuPont Kapton flexible printed circuit polyimide film to demonstrate the conformal nature. High-speed carbon-nanotube-based field-effect transistors (FETs) function as switches to route the RF signal go through different segments of the true-time delay lines. The FET switch exhibits an on–off ratio of over 1000 and current of 3.6 mA is obtained at a low source–drain bias of 0.8 V. The 2-bit azimuth beamsteering angles of the PAA are measured and confirmed to agree well with simulation values.