Broadband microstrip antenna is realized by fabricating the patch on lower dielectric constant thicker substrate. The proximity feeding technique is simpler and more commonly used technique to realize broadband microstrip antennas for substrate thickness greater than 0.06l0. In proximity fed configuration the coupling strip is either placed below the patch or it is placed inside the slot which is cut on the patch. However, design guidelines for the coupling strip parameters are not available. In this paper, a broadband proximity fed equilateral triangular microstrip antennas at different frequencies over 800 to 5000 MHz frequency band are designed. By using the optimum designs, a formulations for strip dimensions and its position below the patch for given substrate thickness, are proposed. The proximity fed configuration was further designed using proposed formulations at different frequency in the same frequency bands. An optimum response with a loop formed inside the VSWR = 2 circle is obtained. Further proximity fed broadband configurations of pair of slot cut equilateral triangular microstrip antenna is proposed. It gives a bandwidth of more than 300 MHz (> 25%) with broadside radiation pattern and gain of more than 7 dBi over the bandwidth.
展开▼
