Very Small Dual Band-Notched Rectangular Slot Antenna With Enhanced Impedance Bandwidth

A very small coplanar waveguide (CPW)-fed rectangular slot antenna with dual band-notched characteristics for super ultrawideband (UWB) applications is proposed. This antenna consists of a rectangular slot, a beveled rectangular patch, two S-shaped slits cut in the ground plane and an elliptical ring slot (ERS) etched in the patch. The corners of a simple rectangular patch are beveled to improve the impedance bandwidth, especially at the middle frequencies of the band. In addition, a pair of semicircle slots is etched in the ground plane to enhance the bandwidth to more than 23 GHz. A pair of S-shaped slits connected to the rectangular slot, and an ERS cut in the beveled rectangular patch, is employed to create band-notched performances in WiMAX and WLAN spectrum, respectively. The proposed antenna has a very small size of 15 × 15 mm², and therefore, it is one of the smallest UWB slot antennas that have been reported until now, and provide a very wide impedance bandwidth from 2.6 to more than 23 GHz for VSWR <; 2 with dual band-notched properties.

I. Introduction

Regarding the approval and allocation of the frequency band between 3.1 and 10.6 GHz by the Federal Communication Commission (FCC), ultrawideband (UWB) communication systems have become one of the most developing technologies in recent years. UWB systems have advantages such as low cost for short range communication, low propagation power, high data rate, remote sensing application, and highly secured environment. On the other hand, commercial UWB systems need compact inexpensive antennas with wide bandwidth and good radiation properties. UWB antennas have been broadly employed to wireless communications, imaging, and wireless sensor networks. With progress of wireless communication systems, more applications have been employed to mobile wireless dongles with smaller size and lighter weight. It is recently noted that small UWB antennas are needed for some medical applications such as microwave imaging for breast cancer. The sensors generally have restricted size, capability, and battery life; hence, UWB antennas are suitable for communication between the sensors due to its low-cost and low power consumption [1].