Broadband Active Microstrip Antennas

The concept of combining active devices with radiating elements for broadband active antenna design was proposed. An active microstrip transmit antenna was realized by using two sided structure and single-ended one-stage amplifier configuration. A 24 percent bandwidth, which is about 6 time that of the passive patch, was achieved both in terms of active reflection coefficient and flat gain of radiation, and about 9dB extra gain was obtained in the working band. The results are attractive for broadband MIC active array design and probably the same concept can be used in broadband MMIC applications such as in radar and satellite communication.