  This study presents a nonreciprocal-beam phased-array antenna constituted of
phase-gradient patch radiators integrated with transistor-based nonreciprocal
phase shifters. Such an antenna exhibits different beams for transmission and
reception states. The proposed phased-array antenna provides power
amplification for both transmission and reception states, which is of paramount
importance in most practical applications. In addition, in contrast to the
recently proposed time-modulated antennas, the proposed nonreciprocal-beam
phased-array antenna introduces no undesired time harmonics and unwanted
frequency conversion, requires no radio frequency bias signal. Furthermore, the
nonreciprocal phased-array antenna is lightweight and is amenable to integrated
circuit fabrication. The transmission and reception beam angles, the beam
shapes, and the power amplification level may be easily tuned by changing the
direct current (dc) bias of the transistors and phase of the passive phase
shifters. Such a nonreciprocal-beam phased-array antenna is expected to find
military and commercial applications.
