Novel destructive-interference-envelope detector for high data rate ASK demodulation in wireless communication receivers

This paper reports on a novel ASK demodulator architecture suitable for receiver circuits in wireless communication applications. The proposed topology targets the theoretical limitation of the maximum achievable data rate or base band bandwidth with respect to the carrier frequency of standard envelope detector approaches. The circuit comprises a balun to split the input signal into two 180° out-of-phase signals and a Schottky diode detector for each branch to convert the modulated RF signal down to base band. Due to the combination of both signal paths the carrier frequency is canceled out, for which reason the novel demodulator topology is named destructiveinterference- envelope detector (DIED). In order to demonstrate the capabilities of the new concept a W-band demodulator MMIC was designed and realized. The MMIC is based on a 35nm InGaAs metamorphic HEMT technology and contains optimized monolithic integrated planar zero bias Schottky diodes. It shows a measured carrier suppression of 65 dB at 102.5 GHz. The measured voltage responsivity for a high load impedance is 6760V/W for low input power levels. The simulated base band bandwidth of 25 GHz leads theoretically to an achievable data rate of up to 50 Gbit/s. First time domain measurements showed a data rate of 26 Gbit/s, which is also the limit of the characterization setup.