Synthesis of Continuous Source Current for Gain Enhancement and Sidelobe Suppression of High-Order Mode Dipoles

A synthesis method of continuous source current on a high-order mode dipole is proposed to enhance gain and suppress sidelobe levels (SLLs) based on compression coefficients. First, a high-order mode dipole with the current distribution determined by designed compression coefficients is proposed to generate a typical continuous source. Then, a pattern synthesis method of continuous source current is presented to enhance gain with desired SLLs by calculating the compression coefficients. Finally, the fifth-order mode dipole is designed to verify the proposed synthesis method. Both measurement and theoretical prediction show the gain of 6.6 dBi and an SLL of −13.3 dB by the single dipole of the length of 1.5 wavelengths at 3.25 GHz. Compared with an array composed of three convention half-wave dipoles, the proposed fifth-order mode dipole of a similar length achieves a gain increase up to 1.13 dBi, or an effective length increases up to 30% while the SLL keeps unchanged.