Design of Programmable Digital Control Attenuator for Microwave Receivers

High performance wideband attenuators with variable attenuation are considered to be challenging to design. In this paper, we proposed a cost-effective high performance programmable digital attenuator with frequency range from DC - 30 GHz. The programmable attenuator can be set by the least configurable step of 0.5 dB and a maximum step of 31.5 dB using a 6-bit input code. The efficiency of the device is enhanced by the implementation of a metal housing that mitigates electromagnetic interference (EMI) internally and externally. The performance of the proposed design is validated using CST Microwave Studio and AWR Microwave Office. The results show that the proposed attenuator exhibits a minimum insertion loss of 4.3 dB with a return loss greater than 10 dB over a wide range of frequencies. The proposed programmable digital attenuator can be utilized where high performance, wide operating bandwidth, and cost-effective solution is required to integrate in microwave receivers.