Design of a Compact Microstrip Filtenna for Miniaturized Devices to Access Internet of Things Using Long Term Evolution

A filtenna or filtering antenna has both radiation and filtering functions and is an important module for the RF front-end of wireless devices. The main function of a filtering antenna is to filter out the out-of-band interferences from the adjacent bands. In this paper, the design of a compact coplanar microstrip filtering antenna at 2.6GHz band is presented. The antenna is designed for the miniaturized devices for the city connectivity to access the internet of things (IoT) services over 2.6GHz long term evolution (LTE) gateways.  Filtering antenna is designed using hairpin bandpass filter integrated with semi-circular microstrip antenna. Filtering antenna is designed by computer simulation technology (CST) software and measurements are performed by vector network analyzer. Good impedance matching at 2.6GHz band is obtained for the filtering antenna by choosing appropriate dimensions of the hairpin bandpass filter.  The simulated 10dB return loss bandwidth of filtering antenna is 4.65% with maximum gain of 1.9dB. Measured and simulated results agree well for the semi-circular filtenna.