The Design Of K Band MMIC Multi-function Power Amplifier Chip

Microwave power amplifier (PA) and switch are the key components in active phased-array radar transmit/Receive (T/R) module. This paper present the design and development of a K-band MMIC Multi-Function Power Amplifier (MFPA) chip. The motivation behind this development is to reduce the size and lightweight, increase reliability for an active phased-array radar T/R module by integrating the PA and switch on one MMIC chip.We studied the design method for high power added efficiency (PAE) and low loss MMIC MFPA chip from PA parameters definition and stability analysis, principle of microwave switch and match network. A 0.15um GaAs pHEMT process was chosen to fabricate this K-band MMIC MFPA chip. Load pull technology was used to design the high PAE power amplifier, and an actual test data model was built in switch design to get accurate result. The entire circuit has been co-simulated to ensure the performance can reach the requirements of the project.Two test and measure system were designed and built to measure performance parameter after the K-band MMIC MFPA chip was fabricated. One is based on probe station and vector network analyzer for small signal analysis. Another is based on signal generator and power meter for large signal analysis. The test result show that in the work band, the transmission channel can provides a linear gain greater than 21dB, a 19dB power gain and over 30% power added efficiency (PAE) at 2dB compress point with 18.7dBm output power. The receiving channel has an insertion loss of less than 1.2dB. The isolation between the transmission channel and the receiving channel is better than 20dBc. The excellent characteristics of the fabricated K-band MMIC MFPA chip meets the requirements.