BiQuad Antennas for 432 MHz Band

BiQuad Antennas for 432 MHz Band

By: Igor Vakhreev, RW4HFN

In this article we take a look for several designs of BiQuad antennas for the 432- MHz Band. Figure 1 shows classical design of the BiQuad antenna. Figure 2 shows Z of the antenna. Figure 3 shows SWR of the antenna. Figure 4 shows DD of the antenna. The antenna has input impedance 85 Ohm that allows feed it with 75 Ohm coaxial cable.

Adding one shunt wire allows increase the broad band of the antenna. Also the gain of the antenna is increased as well.

Input impedance of the antenna is 200- Ohm so it is possible match the antenna with 50- Ohm coaxial cable with help of 4:1 transformer. Figure 5 shows design of the Shunt BiQuad antenna. Figure 6 shows Z of the Shunt BiQuad antenna. Figure 7 shows SWR of the Shunt BiQuad antenna. Figure 8 shows DD of the Shunt BiQuad antenna.

The BiQuad antenna is not so critical to dimension. It allows use to a wide range of the wires to make the antenna.

Figure 1 Classical Design of the BiQuad Antenna

Figure 5 Design of the Shunt BiQuad Antenna

MMANA file for the antennas may be downloaded at http://www.antentop.org/023/RW4HFN_BQuad_023.htm

Credit Line: Forum at WWW.CQHAM.RU

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