Absfracf-The radiation properties of a spherical phased-array antenna with circularly polarized elements are studied. Each antenna element is assumed to have a cosine @pe of field pattern. It is found that such an array is capable of providing complete hemispherical coverage without appreciable loss of gain. The radiation produced by the array stays circularly polarized in all directions, and the state of polarization is independent of beam steering. A special distribution of elements on a spherical surface is developed. This considerably suppresses the grating lobes in the pattern and thereby makes the antenna array broadband. Numerical calculations are made to determine the directivity and halfpower beamwidth for the radiation patterns produced under various situations.

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This report was commissioned by Ofcom to provide an independent view on issues relevant to its duties as regulator for the UK communication industry, for example issues of future technology or efficient use of the radio spectrum in the United Kingdom. The assumptions, conclusions and recommendations expressed in this report are entirely those of the contractors and should not be attributed to Ofcom.

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Simple modifications of formulas presented by A. A. Oliner are found to allow the determination of the impedance and resonant length of a slot in rectangular waveguide when the guide is filled with dielectric material. The modifications are justified by reference to earlier work by Oliner and others, and are verified by experimental results.