Design of an E-Band Direct Modulator with High Modulation Depth Based on Chip-on-Branch Resonator Structure

The growing demand for network connection and communication in human society has posed significant challenges to current mobile communication technologies. In response, a direct modulation communication technology targeting the millimeter wave and terahertz wave in 6G mobile communication has emerged. With its low-complexity architecture, low power consumption, and high data rate features, it possesses broad application prospects and significant scientific research value. This paper proposes and implements a 76GHz on-chip direct modulator with high modulation depth based on a microstrip resonant circuit and a Schottky diode. This module achieves amplitude modulation of information by sensing the signal level to switch the millimeter-wave source between on and off states. The experimental results demonstrate that the circuit achieves an insertion loss below 4.5 dB at the 75 GHz frequency point, with a switching ratio as high as 32 dB and modulation depth exceeding 99%. In the modulation-demodulation link experiment, it realizes a single-tone modulation rate of 12 GHz and an eye diagram modulation rate of 6 Gbps.