An E Band Wideband Superheterodyne Receiver Front-End Using Large-Dynamic-Range Automatic-Gain-Control Loop

An E-band wideband receiver front-end with stable output power over large input dynamic range is presented in this paper. It adopts a double-conversion superheterodyne structure combined with automatic gain control (AGC) technology to realize the wideband signals reception and dynamic range compression. An E-band mixer is designed based on Schottky diodes which features advantages in broadband and low cost, compared with commercially available chips. The AGC loop in the intermediate frequency circuit utilizes 3 voltage variable attenuators to provide a 78 dB continuously variable gain and uses a logarithmic detector to form an analog feedback loop, which exhibits a stable and high-flatness output power over 73 dB input dynamic range. The measured input dynamic range of the receiver front-end is −55dBm to +5 dBm with output power fluctuation better than ±1 dB, in the operating frequency range of 66.5~75.5 GHz. The power flatness of the output frequency response within the 500 MHz channel bandwidth is better than ±0.5 dB. Besides, the harmonic suppression and spur suppression of the IF output signal is better than 52 dBc and 75 dBc, respectively.