Res-net Microwave Rod Resistors
Rod resistors are a cylindrical type resistor that are used in both RF and microwave applications. They are thin film in nature and can be made of alumina, beryllium oxide, or aluminum nitride.
Because of their thin film construction they can achieve very high frequencies. These frequencies can be as high as 26.5 GHz or even higher in certain applications. Res-net Microwave Inc. is one of the few companies that offer rod resistors in alumina, beryllium oxide, and aluminum nitride materials.
The resistance range for rod resistors is generally from 10 ohms up to 500 ohms, and the resistive tolerances are generally 1%, 2%, or 5%. The temperature range is -65 Degrees Celsius to +175 Degrees Celsius. The resistors are covered with a protective coating of high temperature epoxy in order to insulate them from these temperature extremes.
In addition to these classic thin film rod resistors, they can also be supplied using pyrolytic carbon. These carbon rod resistors also perform very well at microwave frequencies and have the added advantage of being able to work to the temperature of +200 Degrees Celsius. The sizes of the carbon resistors mimic those for the other thin film types. These carbon rod resistors will have a negative temperature coefficient as compared to the other resistors which will have either a plus or minus 100 ppm TC.
The power ratings can go from 0.050 watts all the way up to 75 watts, depending upon the material used. They are used extensively in the RF and microwave industries especially in the manufacture of other components such as, SMA terminations.