Abstract: According to the requirements of small size, high integration of phased array radar, in this paper, a TR subarray of Ka-band 24 channels based on the silicon-based three-dimensional (3D) heterogeneous integration technology is designed. The TR subarray is formed from 6 subarray units for easy array assembly, and the RF signal inside the silicon-based module is transmitted by the through silicon via (TSV), ball grid array (BGA) is used to be interconnected with antenna array unit. The TR array unit size is 21.00 mm×14.00 mm×2.85 mm. The test result shows that in the range of 32 GHz~34 GHz, the receive gain of each channel is no less than 20 dB, and the transmit output power of each channel is no less than 23.8 dB, the TR subarray also has the functions of 6 bit phase shift and 5 bit attenuation.