A novel miniaturized loaded line phase shifter

Introduction Phase shifter (PS) in a phased array antenna shifts phase of incoming RF signal depending on control input, enabling antenna main beam to be steered at a faster rate without rotating antenna mechanically. Demand for high performance WLAN system at low cost has necessitated development of a miniaturized PS with reduced loss at low cost. Design and development of various types of PSs (switched line, reflective line, loaded line and highpass and low-pass types) are reported. Out of different types of PSs, loaded line PS offers simplicity and low insertion loss. Practical design of C-band MIC PS using pin diodes is reported. Miniaturized PSs have been reported using MEMS technology, MMIC technology and metamaterials. In addition, fractal technique has been used to reduce size of antenna. Also, usage of Koch fractal in miniaturizing a branch line coupler and a hybrid coupler is reported. This paper presents a reduced size Koch fractal based 3-bit loaded line PS, of which a single bit loaded line section was fabricated and its performance was tested with conventional PS.