Figure 1. Microstrip Radial Stub

Use the program below to calculate dimension r2 for a radial stub.
The radial stub is used to provide a broadly resonant RF short circuit.
When cascaded with high impedance quarter-wavelength transmission lines,
the radial stub can provide an effective decoupling network for microwave
amplifiers and other active components.
The range of dielectric constant (Er) over which the results are valid is 2 to 15.
The frequency range over which the results are valid is 0.3GHz to 30GHz.
The formulas used are the work of Dr. H. A. Atwater of MIT Lincoln Labs, as published in
the November 1985 issue of Microwave Journal.

UnitsInches millimeters
Angle alpha 90 60
Substrate Er Dielectric Constant (range 2-15)
Frequency GHz (range 0.3 to 30)
Substrate Height
Radius r1