Proactive Conformal Waveguide Slot Array Antenna to Synthesize Cosecant Squared Pattern Based on 3-D Printing Manufacturing Process

It is difficult for a standing-wave waveguide slot array antenna to generate a complex beam shape in H-plane, such as the cosecant squared pattern. The reason is that a conventional standing-wave waveguide slot array antenna cannot flexibly and independently adjust the amplitude and phase of radiating elements. In this article, a proactive conformal waveguide slot array antenna is designed with the cosecant squared pattern in its H-plane. It is able to control the element phase by proactively curving the array shape. That means the antenna shape is employed as a new parameter to break the limitation in the phase control. Based on this, the proactive conformal waveguide slot array antenna can modulate the element amplitude and phase independently to form the desired complex far-field pattern. The commercial selective laser melting (SLM) technology is applied to print the curved antenna after carefully considering the printing direction and slot shape. A 35 GHz prototype antenna is fabricated and measured. Good performance can be observed in the measured results.