A wide-band circularly polarized antenna

The design construction and testing of a wide-band circularly polarized antenna suitable for ionospheric research is described. The antenna operates in the range 2 to 7 MHz. Simple design formulas are given for the required broad-band phase shifting networks. Broad-band dipole antennas are used and suitable "balancing networks" are developed to match these antennas to the phase shifting networks ever the frequency range. A satisfactory compromise solution is found to the problem of matching the networks to the receiver using a broad-band transformer. Measurements of the rejection ratio of the system show that it is always better than approximately 16:1 over the required frequency range.