Design Of Beam Steering System In Millimeter Wave Cone-borne Phased Array

Due to its fast and smart beam scanning, phased array has been widely used now. In some special applications of high-speed carriers, phased array has to be conformed on specific surface to meet aerodynamics requirement and broaden its scanning range. With the consideration of construction of missile and obtaining high gain, conical phased array working at 32GHz has been studied in the paper.Traditional phased arrays are confronted with several difficulties at present, such as narrow beam scanning range, complex phase shifter system and large area feed network. Microstrip antenna with wide beam, phase shifter with high power capacity and series feed configuration with composite right/left handed transmission line (CRLH-TL) are employed to construct Cone-borne Phased Array (CPA) to meet the problems above. Unfortunately, beam steering of CPA is much more complex owing to the following reasons: (1) in the circumferential direction, the space phase divisions between adjacent elements are different; (2) in the axial direction, the varying radius also results in the different phase division between adjacent elements. Based on the traditional beam steering methods, an improved beam steering method is presented through the analysis to CPA. The novel method can reduce greatly the amount of calculation of phase excitation on each element and the number of controlling lines, and consequently simplify the layout and complexity of phase shifter modules.To lower the beam steering complexity further, Phase Phantom-bit Technique and Amplitude Phantom-bit Technique are introduced into the present design of CPA, which can reduce the cascade bits of phase shifters and digital attenuators. Finally, a CPA is designed as an example, and its radiation patterns are also analyzed.