Thus a pin diode is a dc controlled high frequency resistor and if no dc current is present the diode is just like an open circuit.
Pin diode switch ic.
The signal to noise ration of the receiver deteriorates somewhat up to 1 db.
Figure 5 shows a single pole double throw spdt rf switch and its bias circuit.
Connecting the switch driver control circuit to a pin diode such that it can turn diodes on and off by applying a forward or reverse bias is a challenging task.
At a minimum an rf switch based on pin diodes needs a dc blocking capacitor to prevent the dc bias current from reaching the rf output and an rf choke to provide a path for the dc bias current to return while blocking the rf signal.
A pin diode is a diode with a wide undoped intrinsic semiconductor region between a p type semiconductor and an n type semiconductor region.
A diode alone is not a complete and useful switch as it is only the core switching element.
The bias circuit typically uses a low pass filter between the rf circuit and the switch driver.
The pin diode switch can be used for antennas with impedances of from 50 ω up to 75 ω.
It is primarily a function of the thickness of the i region and thicker diodes can operate down to 1 mhz while thinner ones can function into.
What is the frequency range of the pin diode as an rf switch.
Rf switch with pin diodes circuit diagram.
The operated diodes block the disconnected antennas by about 30 db.
There are many unique market applications such as the wireless communications market where new.
Chapter 2 the common pin diode switch configurations are presented followed by sections comparing those features of pin diode switch designs for unique to high power microwave switches and high power lower frequency rf band switches.
Signal losses at the closed diode is negligible.
