Compact Ultrawide-Beam Antenna Array Using Novel Series Feeding Network

This paper introduces a novel compact series feeding network for magneto-electric dipole array, which comprises of a four-port even power divider and stripline to coax transitions. The power divider is realized using a comb-line shaped stripline with four branches. Metal vias are then used to convert the stripline to coaxial cable. In addition, reflection canceling slits are employed to improve the impedance match of the input port. The feeding network is 2 λ0× 0.52λ0× 0.13λ0 in size, where λ0 is the operating wavelength in the free space. Simulations show that, across the desired frequency range from 76 GHz to 78 GHz, the proposed feeding network yields good impedance match (S 11<-15 dB), and the fluctuations of transmissions for all four output ports are lower than 1.2 dB (amplitude) and 20 (phase), respectively. Consequently, the proposed antenna array generates gain of 10 dBi and beamwidth of 180 in E-plane across the desired frequency range. This antenna array can be used in automotive radar integrated on each side of vehicle for collision avoidance detection.