A Flip-Chip Packaged Design of Planar Antenna Array Based on Dual-feed Network for 77-GHz Automotive Radar

This paper presents a 77-GHz flip-chip packaged planar antenna array based on dual-feed network. The dual-feed network is consisted of a single substrate integrated waveguide line (SIW) and an array of microstrip line. Wideband transition between SIW and microstrip line is obtained by minimizing the active reflection coefficients. To improve equivalent isotropically radiated power (EIRP), the conventional method of antenna array and enlarged transmitted power are generally used for 77-GHz band. However, these methods will narrow the operating bandwidth, increase the circuit sizes and difficulty in transmitter design. The dual-feed network can simplify the design and decrease the insertion loss and circuit size. Moreover, the dual-feed network can maintain the same bandwidth as the single-feed network, and can also realize on-antenna power combining. In this work, a planar series-fed linear antenna array is taken as an example. By tapering the patch width, the desired radiation pattern is synthesized according to the Dolph-Chebyshev magnitude distribution. Then chip is flip-chipped onto the dual-feed network connecting with antenna array. Broadband flip-chip interconnection between chip and dual-feed network is achieved by properly designing the grounded coplanar waveguide (GCPW) line on PCB. The proposed flip-chip packaged antenna array based on dual-feed network has great potential for automotive radar.