Abstract:
Realization of simultaneous transmit and receive
(STAR) wireless systems is desirable for spectral efficiency but
challenging due to difficulties in isolating the receiver from
the transmitter. A twin-pair STAR architecture based on two
identical sequentially-switched delay line (SSDL) circulators is
proposed for STAR. The twin-pair approach uses one circulator
as a real-time model of the other circulator which is used for
communication, thereby allowing cancellation of transmit signals
from the receiver before reaching the first low-noise amplifier
(LNA). A wideband SSDL circulator is designed and characterized
to study its suitability in the proposed STAR architecture.
The circulator has spur-free (over-multiplexed) operation up to
48 MHz and under-multiplexed operation up to 1.0 GHz with an
insertion loss < 10 dB and isolation > 25 dB.