Mechanically frequency reconfigurable antenna for WSN, WLAN, and LTE 2500 based internet of things applications

摘要

In this paper, the concept of a novel mechanically reconfigurable antenna withspectral diversity, for internet of things (IoT) applications is presented. Theprototype consists of a rectangular microstrip patch antenna placed upon adielectric slab with four end-to-end cavities that are perceived as binary bits.The status of each bit depends on the material filling it. Since four cavities areincluded in proposed system, a total of 16 combinations, each yielding uniqueimpedance characteristic, are exhibited. Here, FR4 epoxy (εr = 4.4 andtanδ = 0.02) is used as substrate with 2.4 mm thickness. The same material isused to fill the cavities in one case, while, in the second case the cavities arefilled with Rogers RT/duroid 6010/6010LM ™ material that has dielectricconstant, 10.2. It is shown that by using a higher dielectric constant materialas filler, the range of variation of resonant frequency can be increased. In bothcases, the prototype exhibits capability to reconfigure its operating bandwidthfrom 2.4GHz WLAN (2400-2480 MHz) to LTE2500 (2496-2690 MHz). Besides,for some combinations, the prototype covers a frequency span beyond LTE till3000 MHz for wireless-sensor-network based applications. One among thepotential application of the proposed design as a chipless RFID tag is also discussedin this work.