Introduction:As technology advances, the need for wireless connection has dramatically increased. With the growing need for wireless connection, new and improved antennas are desired. It is our goal to reduce the size of patch antenna for 2.42-2.48 GHz, which also cheap in manufacturing cost, space saving and easier to incorporate into handheld or small electronics. It has come to us that, folding a patch antenna will reduce the required surface area yet perform the desired functions. For our senior design project, our group would like to propose an idea of designing a folded rectangular patch antenna.
The folded patch antenna is omni-directional because its radiation pattern capable of containing a strong field polarization in any cut plane. The folded patch will be feed by a microstrip. Folded patch is a patch antenna where the rectangular patch it self will be folding around a two layer thick dielectric and the ground will be buried in between the two dielectrics.
Our antenna design is balanced but it can be fed by an unbalanced transmission line such as the microstrip. Also, feed line impedance can be arbitrary chosen to achieve good matching impedance. However, one of the disadvantages of the microstrip is that it provides a fairly narrow bandwidth especially for high permittivity substrates. Also, the reason for using high permittivity substrate is because it brings down the resonating wavelength. Smaller wavelength means smaller size antenna due to its relationship (antenna size is calculated upon wavelengths) (Fig. 1). Also because that the wavelength is directly tied to the dimension and frequency of the patch; therefore, patch antenna are better used at high frequency so that it can save space yet still offers the above characteristics.
Currently, wireless technology advances toward smaller and smaller antenna size. Products such as GPA receiver, Bluetooth receiver...