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900 MHz Dipole Antenna
After moving and installing an anechoic chamber, we needed to test the shielding effectiveness. We decided to build a matched set of 900 MHz Dipole antennas.
We started by designing a half wave dipole antenna.
There is some good material on this topic at:
We found that we needed to design three things.
- Antenna elements
- Impedance Transformation Circuit
We used copper tubing from a hobby shop for our antenna elements.
This paper covers the Balun design we used:
Impedance Transformation Circuit
The impedance of the Dipole Antenna is 75 ohms and we were designing this for a 50 ohm system so we needed to design an impedance transformation circuit.
This is a great tool for calculating values for this circuit.
The antenna worked out great. Here is a picture of the final antenna with the enclosure cover removed.