Surface acoustic wave (SAW) impedance element antenna duplexers provide com
pact, high performance. front-end components apt for industrial fabrication
. We describe investigations on the design and modeling of a compact ISM an
tenna duplexer fabricated oil a 36 degrees YX-cut LiTaO3 substrate based on
SAW impedance elements. In particular. we have performed 3-D modeling of t
he inductive and capacitive electromagnetic couplings caused by the package
parasitics for the duplexer. The use of a 1:3 IDT structure for the reduct
ion of the passband width is discussed. The frequency response of the duple
xer is predicted with the help of circuit simulation: the modeling is refin
ed by optimization of the model parameters to improve the fit between the m
easured and simulated responses. We also report scanning optical imaging of
the acoustic field within the resonator structures with the help of laser
interferometry; this provides insight into the loss mechanisms beyond that
attainable in mere electric measurements.