Intermediate Frequency Circuit Components for Integration of on-Chip Amplifier With THz Detectors

The demand for THz detectors for beam diagnosis and alignment at THz generating accelerator facilities increases continuously especially for room temperature applications. The Zero-Bias Schottky Diode (ZBSD) and field effect transistor (TeraFET) based Terahertz (THz) detectors are well suited for both, signal power detection at DC as well as Pulse shape diagnostics by down-conversion at intermediate frequencies (IF). The limited signal strength due to the roll-off factor of the low pass filter characteristic of the detectors at higher THz frequencies requires wide-band amplifiers to enhance the IF signal from a few µW to nW well above the noise floor of the subsequent post detection electronics. Using external amplifiers would enhance the signal losses even further due to additional connectors and rf-cable losses and degrade the signal to noise ratio (SNR). In order to maximize the SNR, we propose to have an on-chip amplifier integrated in the detectors intermediate frequency (IF) circuit in the same housing. In this work, we present the design and parametric analysis of components for transition to an IF circuit, which will be integrated in the ZBSD and TeraFET on chip with amplifier. A rigorous design analysis has been done to find the optimal parameters for wide-band operation in order to enhance the detector’s resolution to capture pulses in the pico-second range with the help of fast post detection electronics.