Ku波段6bit数字衰减器MMIC的小型化设计

基于0.25μm GaAs增强/耗尽(E/D)型赝配高电子迁移率晶体管(PHEMT)工艺,设计并实现了一款集成了6 bit并行驱动器的数字衰减器单片微波集成电路(MMIC)。该衰减器采用T型衰减网络结构,不仅缩小了芯片面积,并且可实现较好的衰减精度和衰减附加相移。芯片在片测试结果表明,在-5 V电源电压下驱动器的静态电流为1.8 mA,响应速度为25 ns。在9~18 GHz频率范围内,衰减器芯片的插入损耗不大于3.6 dB,均方根衰减精度不大于0.7 dB,衰减附加相移为-2°~4°,输入电压驻波比(VSWR)不大于1.25∶1,输出VSWR不大于1.5∶1。芯片尺寸为1.6 mm×0.6 mm×0.1 mm。该电路具有响应速度快、功耗低、面积小、衰减附加相移小等优点,可广泛应用于通信设备和微波测量系统中。

Design of a Compact Ku Band 6 bit Digital Attenuator MMIC

A digital attenuator monolithic microwave integrated circuit(MMIC) integrated with a 6 bit parallel driver was designed and implemented based on the 0.25 μm GaAs enhancement/depletion(E/D) mode pseudomorphic high electron mobility transistor(PHEMT) process. The attenuator adopted a T-type attenuation network structure, which reduces the chip area and achieves better attenuation accuracy and attenuation additional phase shift. The test results on wafer show that under-5 V supply voltage the static current of the driver is 1.8 mA and the response speed is 25 ns. In the frequency range of 9-18 GHz, the attenuator chip achieves an insertion loss of no more than 3.6 dB, a root mean square attenuation accuracy of no more than 0.7 dB,an attenuation additional phase shift from-2°to 4°, an input voltage standing wave ratio(VSWR) of no more than 1.25∶1, and an output VSWR of no more than 1.5∶1. The attenuator chip size is 1.6 mm×0.6 mm×0.1 mm. The circuit has the advantages of fast response, low power consumption, small area, small attenuation additional phase shift, and can be widely used in communication equipment and microwave measurement systems.