Harmonic radar transponder for microsensing systems

A harmonic transponder design suitable for microsensing systems is presented. The transponder is a passive device and operates at millimeter-wave frequencies to reduce its size and weight. The receive band is 38-38.5GHz and the transmit band is 76-77GHz. The transponder is formed from two planar microstrip patch antennas and a frequency multiplier circuit, and its minute size and weight make it an attractive option for tracking small objects or animals.