SIW based compact and dual-band equilateral triangular antennas

In this paper, a substrate integrated waveguide (SIW)-based equilateral compact and dual band triangular antennas have been proposed. A SIW-based coaxial fed equilateral triangular antenna has been initially considered. The antenna is found to resonate at 5.28 GHz corresponding to U-NII-2 WLAN band. Two sides of the said antenna are made perfect electrical conductor wall with array of metallic vias and the third side is kept open which acts like a perfect magnetic conductor (PMC) wall. A single slit has been introduced on the PMC wall of the initial antenna which causes a decrease in resonating frequency from 5.28 to 4.29 GHz. The antenna has been further miniaturized by introducing another parallel extra slit on the PMC wall which leads to a decrease in the resonating frequency to 3.3 GHz. The former antenna with single slit is found to exhibit 33% miniaturization while the latter with double slits reflects 56% miniaturization. By changing the coaxial feed location of the initial antenna at off-axis position, a dual band antenna has been realized. The dual band antenna is found to excite both TE101 and TE202 modes efficiently with corresponding resonating frequencies at 4.18 and 8.85 GHz. The prototypes have been fabricated on Arlon AD270 substrate and simulated results are compared with the measured ones. A good agreement has been observed between the simulated and measured results.