The phase shift and loss problems of microstrip ferrite phaser are investigated. The relative permeability of ferrite substrate and the reduced magnetization of the substrate magnetic circuit are analysed. The calculation formula for phase shift is given

and the factors which affect phase shift are discussed. The expression of conductor attenuation constant for coupled strips on a magnetic substrate is derived

and the formula for phaser insertion loss calculation is given. The theory so developed is used to analyse the phase shift characteristics and insertion loss of a phaser. and a good agreement with the experimental results is obtained. Both the theortical analysis and experimental results show that the so-called "two shortcomings of the meander line phaser-the lower phase shift efficiency and the higher internal resonance loss" can be overcome and a high quality phaser （a 4-bit device

insertion loss = ldB

bandwidth = 20%） can be realized.