A Planar Dipole for Multiband Antenna Systems With Self-Balanced Impedance

Abstract

In this letter, we present a multiframe L-slot planar dipole loaded with a single microstripline for multiband antenna systems. Themultiband is achieved by creating amultiframe L-slot on a host dipole and also by loading the host dipole antenna with a singlemicrostripline to generate a couple of shunts and series of capacitive gaps with an inductive strip, eventually forming LC-like resonators. The antenna supports several wireless communication bands including: LTE bands at 1.7 similar to 1.8 and 2.3 similar to 2.6 GHz; WLAN bands at 2.4 similar to 2.5, 5.2, and 5.8 GHz; WiBro/WiMAX bands at 3 similar to 4 GHz. In addition, to validate the multiband behaviors, we also proposed a simple equivalent circuit for the designed antenna in which biconical transmission lines were adopted to model the host dipole sections. The simulation, fabrication, and measurement of the proposed antenna were implemented. As a result, its reflection coefficients vertical bar S-11 vertical bar were found to be better than -7 dB for most operating frequencies along with a sufficiently large bandwidth and good radiation patterns.