MULTIBAND TRIANGULAR PATCH ANTENNA

Abstract

In telecommunication, there are several types of microstrip antennas (also known as printed antennas) the most common of which is the microstrip patch antenna or patch antenna. A patch antenna is a narrowband, wide-beam antenna. Microstrip antennas are relatively inexpensive to manufacture and design because of the simple 2- dimensional physical geometry. They are usually employed at UHF and higher frequencies because the size of the antenna is directly tied to the wavelength at the resonant frequency. A single patch antenna provides a maximum directive gain of around 6-9 dB. It is relatively easy to print an array of patches on a single (large) substrate using lithographic techniques. Patch arrays can provide much higher gains than a single patch at little additional cost; matching and phase adjustment can be performed with printed microstrip feed structures, again in the same operations that form the radiating patches. The ability to create high gain arrays in a low-profile antenna is one reason that patch arrays are common on airplanes and in other military applications The most commonly employed microstrip antenna is a rectangular patch. The rectangular patch antenna is approximately a one-half wavelength long section of rectangular microstrip transmission line. When air is the antenna substrate, the length of the rectangular microstrip antenna is approximately one-half of a free-space wavelength. As the antenna is loaded with a dielectric as its substrate, the length of the antenna decreases as the relative dielectric constant of the substrate increases. Here a rectangular patch antenna resonating at 2.4 GHz is designed and their reflection coefficient, radiation pattern & polar plot is drawn & analysed. Now the Triangular patch antenna working on same resonant frequency is designed which is having less size compared to the rectangular patch antenna. The triangular microstrip antenna is one of the shapes of microstrip antennas which have radiation properties similar to that of the rectangular antenna but with the advantage of being physically smaller. The simplest of triangular shapes is equilateral antenna which has more directivity with compact size. In this project rectangular patch has been designed to operate at resonance frequency of 2.4 GHz for Wi-Fi application. Then a triangular patch antenna of same resonating frequency is designed. It has been seen from the result that the size required for the triangular antenna to resonate at the same frequency is less as compared to rectangular patch antenna. Then triangular slots have been made in the same triangular patch antenna so that it is converted into the fractal antenna and the design is simulated. The result obtained for two fractal geometry shows that the return loss of the antenna at 2.4 GHz is less as compared to the same dimensions of triangular patch antenna. Fractal antenna is having many advantages over the simple patch antenna like miniaturization, better input impedance matching & wideband / multiband behaviour. A new triangular multiband patch antenna has been designed to operate at resonant frequencies 1.1 GHz, 2 GHz & 3 GHz.. again the triangular slots are cut in this design to make it fractal antenna so we get the lower return loss at resonant frequencies.