Flat-Top Beamforming Synthesis Method Achieved With High-Order Mode Dipoles

A synthesis method for high-order mode dipoles was proposed to enhance beamwidth and reduce sidelobe levels based on nonuniform compression. The current distribution along a high-order mode dipole was controlled by the selected compression coefficients. By utilizing multiple independent compression coefficients, significant flexibility was provided to the dipole, facilitating the achievement of flat-top beamforming. To achieve the desired beamwidth and sidelobe levels, a system of equations was formulated to solve for the compression coefficients, thereby enabling flat-top beamforming. Finally, a printed dipole operating in the seventh-order mode was designed and measured to verify the proposed synthesis method. Experimental results demonstrated that the antenna achieved a sidelobe level of −15 dB and a 1 dB beamwidth of 90°, in accordance with theoretical expectations.