Electronically Tunable Reflection Type Phase Shifter Using PIN Diode As A Variable Resistor

This paper presents a new attempt to utilize the PIN diodes as variable resistors to realize a continuously tunable phase shifter. A diode is used in parallel to a capacitor. Thus, the diode resistance and hence the imaginary part of the impedance can be varied. The tuning range of a varactor capacitance is usually limited to 1:2. However, the resistance of a diode can vary from a few Ohms to a few kilo Ohm. Therefore, a much wider tuning range is possible. The next challenge is to reduce the power lost in the real part of the impedance. As an example, a reflection-type phase shifter (RTPS) is designed and implemented at 2.4 GHz.