Examination of near-field vehicular antenna coupling

The authors explore the limitations of using the far-field antenna coupling equation to predict the coupling between two VHF (30 to 88 MHz) antennas for separation distances as small as 0.05 wavelengths. Results of finite ground plane and scale model antenna coupling measurements conducted in an anechoic chamber were compared to antenna coupling values calculated with the far-field antenna coupling equation. The results indicate that the far-field dipole coupling equation can be used to predict the coupling (+2/-3 dB) between two low-gain 0.25-wavelength monopole antennas mounted on a flat plate for close spacings of 0.4 to 2.5 wavelengths.<
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