180/spl deg///spl alpha//spl deg/ combined phase shifter

Strip line phase shifters are key devices widely used in phased array antenna application. To avoid the grating-lobes through a wide range of scanning angle, the element spacing in the array should be less than about /spl lambda//2. In order to arrange all of the phase shifters in the phased array antenna on a single plane, each phase shifter should be as compact as possible. The digital phase shifter composed of cascaded several bit elements (180/spl deg/, 90/spl deg/, 45/spl deg/, 22.5/spl deg/...), is widely used for phased array application. We propose 180/spl deg///spl alpha//spl deg/ combined phase shifter, which consists of 180/spl deg/ switched-line section and arbitrary angle (/spl alpha//spl deg/) loaded-line section. This proposed phase shifter operates as a 2-bit phase shifter, and has both physical and electrical advantages, i.e., its compact size and small phase shift deviation. This paper presents the basic configuration of the proposed phase shifter, and also presents an example of the characteristics in the case of a /spl alpha//spl deg/=45/spl deg/ calculated by the method of moment.