Broadband Antennas for the Double Quantum Well Terahertz Detector

This work is focused on realizing terahertz detectors based on the idea of photon-assisted tunneling (PAT) in the double electron layer tunneling transistor (DELTT). The detector employs a broadband antenna integrated lithographically with the DELTT. The antenna should be broadband to take full advantage of the electrically tunable characteristic of the DELTT device. This work deals with the analysis and design of broadband antennas to efficiently couple THz radiation to the DELTT device. Numerous bowtie and log- periodic antenna structures have been designed and simulated that have broadband impedance characteristics. The electromagnetic simulator IE3D is used to perform simulations. Measurements on sample antennas were also performed to examine the agreement between simulation and experimental results. A key feature of this work is the development of an equivalent circuit model for the combined antenna and the DELTT device that could be valid at THz frequencies. The development of such a model is extremely important to match the antenna impedance to the device impedance, which is key to enhance the coupling efficiency.