Friday, June 20, 2014

Antenna for 432 MHz band with 21 dB gain

Antenna Backscatter length 4L. Antenna is shown in Figure. The antenna has a gain of 21.4 dB
with respect to increased half-wave dipole. The excitation system consists of a vibrator and a reflector nine directors. Reflector antenna configured as a disc whose diameter is equal to one wavelength. The vibrator has a length KL / 2. The first director is spaced a distance from the vibrator W-D1 = 0,2 L, each next - at a distance of 0,4 L from the previous one. The lengths of all Directors are equal (length director depends on its thickness). Full length of the excitation system is 4L. Large M reflector antenna has a diameter D, = 4L. In front of him at a distance of 0.25L. placed another ring-shaped reflector, the external diameter of which is 6L, and the internal - 4L. Studies have shown that this antenna has a gain of 8 dB greater than the antenna Uda-Yagi length 8L. Height w reflector ring is usually 0,25 L. Research has shown that an additional effect on the height of the antenna gain. The second figure shows the dependence of gain for one value of the diameter D = 2,35 L. Additional strengthening is added to strengthen that implements regular antenna is Backscatter flat reflector. An antenna with a large gain value for the 432 MHz band encounters certain difficulties, especially associated with the manufacture of a reflector of a sufficiently large diameter, since in this case it is necessary to ensure the necessary rigidity of the reflector and the carrying beam. Advantages of this antenna: high gain, power and simplicity of the relatively small size of the antenna criticality.

antenna fo 432 mhz

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