Uncooled THz/sub-THz Rectifying Detectors: FET vs. SBD

Nonlinear photoresponse of field effect transistors terahertz detectors at high irradiation intensities

“…28. In that work, it was assumed that c ¼ 2 for matching with lenses and/or wide aperture antennas, and c ¼ 4 for other cases.…”

Parasitic Effects Affecting Responsivity of Sub-THz Radiation Detector Built of a MOSFET

“…The model introduced there can be employed to calculate the responsivity of a detector built of siliconbased MOSFETs of various sizes, in a procedure which to some extent resembles the approach in [13]. However, instead of the channel impedance Z 0 (as done in [12]), the Z gs (f, W, L) impedance calculated in Section IV should be used in order to obtain a more realistic prediction of the responsivity.…”

“…However, all the reported circuits based on MOSFETs seem to rely on a rough 1-dimensional model of the detection mechanism itself [7,8]. It is believed that the antenna should be well-matched to the device in order to improve the responsivity of the device as shown in [12] or [13]. The detectors known in the literature are typically equipped with narrow-band antennae which are expected to work in a well-defined frequency band as shown in [9][10][11][12].…”

“…The overall goal of this paper is to extend [12] and to provide some technological information to the on-going discussion dedicated to construction of improved versions of MOSFET-based detectors of the sub-THz radiation. Although the role of parasitics in the operation of such detectors was already mentioned in [13], the major focus of the paper was different, and it does not answer questions related directly to the layout of FETs employed in detecting circuits. The work presented herein aims at filling this gap.…”

“…The work presented herein aims at filling this gap. Additionally, the authors' intention is also to indicate that some available explanations (e.g., in [13]) of the relationship between the device's responsivity and its bias voltage based on the power transfer between the antenna and the transistor channel should be rather treated as an approximation only. It seems rather that at very high frequencies, the role of the parasitics becomes dominant, which makes much less significant the influence of the actual level of the channel impedance on the effective impedance that loads the antenna.…”