A simple and low-cost multiple beam phased array is designed using a microstrip Rotman lens and multi-line phase shifter controlled by a piezoelectric transducer (PET) at Ka-band. A microstrip Rotman lens with five beam ports and nine array ports is used as a feed for a multiple beam antenna array to generate five beams centered at the angles of 0/spl deg/, /spl plusmn/15/spl deg/, and /spl plusmn/30/spl deg/. The lens fed nine-element patch array shows the antenna gain of 10 dBi and sidelobe suppression of 10 dB. Each beam is steered over /spl plusmn/8/spl deg/ using two PET-controlled phase shifters, and the five beams cover /spl plusmn/38/spl deg/ from the broadside.