Planar asymmetric dual diode for millimetre wave detection and power measurement

The design of a simple cost-effective planar semiconductor microwave diode is proposed. The operation is based on hot carrier phenomena and rectification of microwave currents flowing through the structure composed of two diodes connected in series and having different active region areas. A simplified technological process and the use of simplex semiconductor material result in the reduction of both the time and the cost of fabrication of a dual microwave diode. By choosing an appropriate GaAs substrate, two types of microwave diodes were produced simultaneously: one almost demonstrating the ohmic behaviour and the other two having the asymmetrical Schottky-like I–V characteristic. The Schottky-like planar diodes exhibited a higher responsivity to millimetre range microwave radiation and a faster response to pulsed (down to a nanosecond scale) excitation, but the ohmic ones demonstrated better noise properties.