X波段单片集成低噪声接收子系统

报道一种新型 X波段 0 .2 5 μm PHEMT全单片集成低噪声子系统。该子系统由开关衰减电路、采样检波电路和低噪声放大器三部分组成。开关插入损耗仅 0 .5 d B,放大器噪声系数小于 1 .5 d B。当开关控制电压为-2 V,输入电平 <-7d Bm时 ,此系统相当于一个低噪声放大器。在 8.5～ 1 0 .5 GHz频率内 ,整个系统增益大于2 4d B,噪声系数小于 2 .0 d B,输入输出 VSWR<1 .5 ;但当输入电平 >-7d Bm时 ,采样检波电路开始工作 ,打开主放大器前的开关衰减器 ,限制输入功率进入 LNA。输入功率越大 ,反射越大。在开关控制电压为 +2 V时 ,无论输入功率多大 ,开关关闭通道

X-band Monolithic Low Noise Receiver Subsystem

This paper describes a new kind of 0.25 μm PHEMT X band fully monolithic low noise receiver subsystem that consists of a switch attenuator, a sampling detector and a low noise amplifier. The insertion loss of the switch is only 0.5 dB and the noise figure of LNA is only 1.5 dB. When the control voltage over the switch is -2 V and input power is less than -7 dBm, the subsystem is a LNA except an additional 0.5 dB loss of the switch. The subsystem has more than 24 dB gain, less than 2.0 dB noise figure and 1.5 VSWR from 8.5 GHz to 10.5 GHz; But when input power level is more than -7 dBm, the sampling detection circuit begins to drive the switch to reduce the signal channel and reflect input power. The more the input power, the stronger the reflection. When the control voltage over the switch is +2 V , whatever the input power is, the swithc turns off the signal channel.