A Tunable Gain Microstrip Antenna for Compact Pattern-Reconfigurable Array

In this letter, a method of tunable gain microstrip antenna for compact pattern-reconfigurable array is proposed. The tunable gain element is realized by integrating a switchable resistive attenuator, which is composed of a RF SP4T and four loading resistors. The method is demonstrated on a six-element sidelobe reconfigurable array operating at 2.45 GHz, which consists of three kinds of tunable gain elements with different gains. The measurements have a good agreement with the simulations and show the first sidelobe level range from -14 to -20 dB of the array at 2.45 GHz in H-plane is achieved based on the tunable gain range from 5 to 1.9 dBi of the elements.