Hello every one.
I want to make quarter wave transformer . how can i get antenna input impedance value at specific point on the circumference ? my patch is circular with 9.5mm radius?
Dear Alaa,
Welcome!
The most staight for ward method is to apply a signal from a signal generator and measure the the voltage at its output terminal and its voltage is already known Vs.
It is important to measure the Vo is a vector.
Then one can determine the input impedance using the relation:
Vo/Vs = Zi/(Zi +Zs)
with Zs=50 ohm , the only unknown is the input impedance Zi.
Best wishes
If your patch is of an ideal circular shape, then the input impedance at any points on the edge is identical. Using a discrete port to check the Z-parameter of the antenna.
Discrete port excitation can give the impedance at any specific point on the antenna. However, an additional inductance in inherently present because of the dielectric height, in the result of discrete port excitation.
I thereby suggest you to
1. Excite antenna through a microstrip line and waveguide port.
2. Go to the waveguide port properties, and move the reference plane to the edge of the antenna.
In-fact, the impedance calculated through smith chart plot of S11, and impedance calculated through Z-parameters remain same for the single port excited antenna.
- Badges
- Science topic