A GaN-HEMT Active Drain-Pumped Mixer for S-Band FMCW Radar Front-End Applications.

Area of Science:

• * Electronics and Electrical Engineering
• * Materials Science
• * Microwave Engineering

Background:

• * Active mixers are crucial components in radio frequency (RF) systems.
• * Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) technology offers superior power handling and efficiency.
• * Drain-pumped (DP) mixers present an alternative topology for improved performance.

Purpose of the Study:

• * To report the first Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) drain-pumped (DP) mixer.
• * To present a method for predicting optimal bias conditions for DP mixers.
• * To evaluate the performance of the DP mixer in a radar-like setup.

Main Methods:

• * Design and fabrication of a GaN HEMT DP mixer prototype.
• * Prediction of optimum bias conditions for high conversion gain (CG) and linearity.
• * Testing the mixer prototype in an S-band frequency-modulated continuous-wave (FMCW) radar setup.
• * Comparison with a fabricated resistive mixer using the same GaN HEMT technology.

Main Results:

• * Achieved a conversion gain (CG) of +10dB and an input third-order intercept point (IIP3) of +11dBm at 3.7 GHz with 20 dBm local oscillator power.
• * Exceeded documented limitations for gain and linearity in similar mixer classes.
• * Demonstrated superior S-band FMCW radar performance with an IF signal-to-noise-ratio (SNR) of +39.7dB compared to +34.7dB for the resistive mixer.
• * Confirmed the DP mixer's capability for system applications.

Conclusions:

• * The developed GaN HEMT DP mixer represents a significant advancement in S-band mixer technology.
• * The proposed design method enables efficient optimization of DP mixer bias conditions.
• * The DP mixer topology shows considerable potential for high-performance radar and other system applications.