A Novel Ultra Broadband 8-45 GHz 4-Bit GaAs Pseudomorphic High Electron Mobility Transistors (pHEMT) Monolithic Digital Attenuator Used for Gain Control of Transceivers

A novel broadband, 8 to 45 GHz 4-bit MMIC digital attenuator which could be used for gain control of transceivers has been designed. The attenuator has been designed with 0.25 ¿m GaAs pHEMT process. Ultra broad bandwidth and high attenuation accuracy has been achieved by using different types of configurations. This attenuator has 1 dB resolution and 15 dB dynamic range. The normalized attenuation accuracy is better than 0.6 dB over all attenuation range and full 37 GHz bandwidth. The reference state insertion loss is less than 6 dB at 20 GHz. The input and output return losses of the attenuator are better than 11 dB over all attenuation states and operating frequencies.