As more devices and services compete for wireless bandwidth in emerging applications such as Internet of Things (IoT) sensors in factories, warehouses, even in “smart homes,” broadband antennas become a key high-frequency component of interest. Numerous antenna technologies are available, but microstrip antennas (MSAs) provide miniature, low-profile solutions for many short-range communications links.
In exploring the different possibilities of MSAs, researchers from the Dwarkadas Jivanlal Sanghvi College of Engineering at the University of Mumbai, India, experimented with the concept of increasing the isosceles angle in isosceles triangular microstrip antennas (ITMSAs) to increase antenna bandwidth. They discovered it is a viable and repeatable approach to boost triangular microstrip antenna bandwidth.
The research team learned that increasing the isosceles angle in a triangular MSA tunes the spacing between the microstrip patch and its resonant modes as part of the path to achieving wider microstrip patch antenna responses. Using extensive computer simulations, inevitably backed by measurements of actual microstrip antenna hardware, the team studied the magnetic- and electric-field patterns of the different microstrip triangle and slot patterns to determine what delivered not only the widest bandwidths, but the most repeatable EM responses.
By tuning the second-order transverse magnetic TM11 mode frequency and third-order TM20 model frequency with respect to the fundamental TM10 mode frequency, they were able to optimize the bandwidth for a particular triangular microstrip antenna pattern. Using slots cut into the microstrip patterns to work with the three resonant modes, they achieved maximum bandwidths of more than 1 GHz (or a 65% bandwidth). Some of the slot-cut patterns also provided broadside radiation patterns with as much as 8-dBi gain.
See “Broadband Variations of Isosceles Triangular Microstrip Antennas,” IEEE Antennas & Propagation Magazine, Vol. 60, No. 2, April 2018, p. 34.