An Extended Ohmic-Biased Transistor Antenna Enabling Signal Transmission for Integrated Sensing and Communication Application

Integrated sensing and communication (ISAC) merges object sensing and positioning with mobile networks, enhancing communication efficiency while expanding functionality of wireless systems. To enable both high-speed transmission and precise localization, ISAC systems demand antennas that offer wide bandwidth within a compact volume. In a previous work [1], Ohmic-Biased Transistor (OBT) antenna is proposed with wideband coverage and small dimensions. However, OBT antennas are receive-only, and therefore are incapable of ISAC applications. This communication proposes an innovative extended OBT antenna with signal transmission capability. This design integrates a monopole antenna with a transmitting circuit, and a receiving circuit. The receiving circuit employs OBT matching, while a novel saturation-biased transistor matching is utilized for transmitting circuit. P-i-n diodes are used for dynamic circuit selection. The antenna possesses a bandwidth spanning from 50 MHz to 2 GHz in the transmit mode and 50 MHz to 1.85 GHz in the receive mode. The antenna provides a transmit gain of 7.52 dBi and a receive gain of 7.4 dBi. Based on this antenna, an image transfer system is realized as a demonstration. The system realizes a maximum signal-noise ratio of 19.4 dB and channel capacity of 6.73 Mbit/s. Experimental results validate its effectiveness and highlight its strong potential for compact ISAC terminals.