An Analysis of the Equivalent Resistance of PIN Diodes at Microwave Frequencies

The PIN diode is an especial charge controldevice. The middle zone of a PIN diode between theheavily doped P-type semiconductor ( P ) and N-typesemiconductor ( N ) is so called region I with highresistivity, as shown in Fig.1. The region I of apractical PIN diode consists of the high resistivity Pmaterial called I(π)-type or high resistivity N materialcalled I(υ)-type. The density of carriers in the region Iis controlled mainly by the applied bias voltage.Therefore, the resistance o…

An Analysis of the Equivalent Resistance of PIN Diodes at Microwave Frequencies

The forward bias equivalent resistance of PIN diodes, an important parameter in applications, is usually measured at lower frequencies. But in fact, due to skin effect the effective conduction area of the region I of a PIN diode decreases as the frequency increases. In this paper, the affection of skin effect to forward bias equivalent resistance is considered and an analytic expression of the equivalent resistance of the region I is presented. In result, the forward bias resistance of a PIN diode at microwave frequencies is much higher than that at DC and low frequencies. It is necessary, therefore, to consider the skin effect of PIN diodes in high frequency applications.