A 124.9 GHz Traveling Wave Switch Direct Modulator Using Different Switch Units

Terahertz direct modulator is one of the most important devices in terahertz direct modulation communication systems. In this paper, a direct modulator based on traveling wave switching scheme is designed. Its working frequency is located at 140 GHz band, and it is a second-order traveling wave switch modulator with two different switch units. In the simulation, the traveling wave switch modulator reaches an overall insertion loss of 4 dB and the on-off ratio of 24.4 dB at 125 GHz. In experiment, a 4.7 dB insertion loss and a 28.9 dB switching ratio is realized in 214.9 GHz. With the frequency changes, the on-and-off states switched and another switching ratio peak is found at 147.2 GHz.