Miniaturized 433 MHz antenna for card size wireless systems

In this paper, a miniaturized 433 MHz microstrip planar antenna will be discussed. The antenna is made for small wireless devices, such as wireless receivers and for small card size indoor readers. The wavelength of the operating frequency is much larger than the available space for the antenna; this makes it quite challenging to have such a small antenna for the desired frequency. Two major techniques are used to accommodate the antenna in the required space, this include shortening the radiating part of the antenna to the ground plane and using a meander line like antenna structure. The main limitation was to accommodate a 433 MHz antenna in a small card size area for an indoor wireless unit. Apart from that, the antenna should be low cost, and with a max gain better than that of a commercially used loop antenna gain of -15 dBi. In this paper we will discuss the development and the performance of such a miniaturized antenna for a frequency of 433 MHz.