In this paper, a fundamental advancement of the basic helix design which expands to array having good bandwidth is proposed. The helix is inserted in a cavity. The result is a new antenna design that offers the performance characteristics and advantages of the conventional helix but in a much more compact physical size envelope. A 4-element rectangular helical array has been designed. For miniaturization and impedance matching, the helical wire is replaced by a rectangular cross sectioned strip. It has been observed that when the helix is inserted in a cavity, it behaves differently from a normal helical antenna. The effects of the cavity on the number of turns, the impedance of total antenna, and the reflection coefficient have been analyzed. The array is designed for 2.4 GHz. The return loss obtained is less than − 10 dB and the bandwidth is more than 1.3 GHz for the array.
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