Experimental and Theoretical Investigation of the Dependence of Oscillation Characteristics on Structure of Integrated Slot Antennas in Sub-terahertz and Terahertz Oscillating Resonant Tunneling Diodes

Abstract

We report experimental and theoretical work on the dependence of oscillation frequency and output power on the offset of a feeding point and the aperture width of a slot antenna in sub-terahertz (THz) and THz resonant tunneling diode (RTD) oscillators. Theoretical analysis shows that the oscillation frequency increases with the offset of the RTD from the center of the slot antenna. Output power also increases with the offset up to the point of the best impedance matching. In the experiment, an oscillation frequency of 504 GHz without offset increases to 593 GHz with an offset of 15 µm (60% of half the antenna length) from the antenna center for a 50-µm-long antenna. The experimental frequencies are in good agreement with the calculation. For the dependence on the width of the slot antenna, a slight increase in frequency is expected theoretically, although the output power is almost invariant. The oscillation frequency increases experimentally to about 345 GHz with a width of 2 µm from about 330 GHz with a width of 4 µm, in reasonable agreement with theory. The increase in oscillation frequency without using short antennas, which results in a decrease in output power, is shown by these experimental and theoretical results.