A cascade RF power sensor based on GaAs MMIC for improved dynamic range application

In this paper, a novel cascade power sensor with improved dynamic range is proposed. The terminating-type sensor and the coupling-type sensor are designed in series for low and high power detection, respectively. This device is designed and fabricated by GaAs MMIC process and MEMS technology. Impedance matching by increasing the slot width of the CPW transmission line is realized to optimize microwave performance. The measured return loss is close to -28dB and -26dB at 8GHz and 12GHz, respectively. For the incident power of 1mW to 100mW, the terminating-type sensor works and the measured sensitivity is close to 0.095mV/mW, 0.088mV/mW and 0.084mV/mW, at 8GHz, 10GHz and 12GHz, respectively. For the incident power with the improved dynamic range of 100mW to 150mW, the coupling-type sensor is adopted and the sensitivity is 9.2μV/mW, 8.6μV/mW and 9.0μV/mW at 8GHz, 10GHz and 12GHz, respectively.