BiQuad Antennas for 432 MHz Band

Adding in the center of the shunt wire an inductor allows adjust antenna resonance frequency that makes the antenna very universal. 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. Gain almost the same as at shunt BiQuad antenna. SWR is lower compare to the shunt BiQuad antenna.

Figure 9 shows design of the Shunt BiQuad antenna with center inductor. Figure 10 shows Z of the Shunt BiQuad antenna with center inductor. Figure 11 shows SWR of the Shunt BiQuad antenna with Center Inductor. Figure 12 shows DD of the Shunt BiQuad antenna with center inductor.

Another modification of the antenna is 3-D BiQuad Antenna. 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. Gain almost the same as at shunt BiQuad antenna. SWR is lower compare to the shunt BiQuad antenna.

Figure 13 shows design of the 3-D BiQuad antenna. Figure 14 shows Z of the 3-D BiQuad antenna. Figure 15 shows SWR of the 3-D BiQuad antenna. Figure 16 shows DD of the 3-D BiQuad antenna.

73! de RW4HFN

Figure 9 Design of the Shunt BiQuad Antenna with Center Inductor

Figure 13 Design of the 3-D BiQuad Antenna

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

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