Electrically Steerable Single-Layer Microstrip Traveling Wave Antenna With Varactor Diode Based Phase Shifters

The design of electrically steerable traveling wave microstrip antenna arrays is presented. Varactor diode based phase shifters implemented on the same metallic layer as the patch elements are used to provide a variable progressive phase shift in the array. Two antennas for the 5.8 GHz ISM band, manufactured as single layer printed designs on a standard PTFE soft substrate, are demonstrated. A ten-element beam-tilting vertical array using transmission type phase shifters is realized, yielding between 11.8 to 13.9 dBi gain for the 0deg to 11deg beam tilt tuning range. Using wide phase tuning range reflection type phase shifters a five-element horizontally scanning array with -32deg to 32deg steering range and 10.9-11.3 dBi gain has been realized.