A theoretical analysis of a modulator based on two coupled resonators is pr
esented in this paper. This modulator exhibits a resonant enhancement in it
s response. It is used as a component of tunneling structures designed for
operation at terahertz frequencies; unlike conventional resonant tunneling
structures, these use triple barriers. Data from optical and electrical mea
surements on a series of devices based on one design of a triple-barrier tu
nneling structure have been analyzed to estimate their behavior at frequenc
ies over 1 THz. The analysis gives values for the resonantly enhanced admit
tance, its bandwidth, the bias-frequency relationship, and the requirements
for a matching circuit to a 50-Omega environment. The results show that on
e existing structure might be used in oscillators working at 1 THz.