^{1}

^{2}

^{3}

^{1}

^{2}

^{3}

Novel and compact CPW-fed antennas are proposed comprised of a fractal patch and modified ground-plane. The ground-plane is truncated at the center and includes dielectric notches at its side to enhance the antenna’s impedance bandwidth. The dimensions of the notches effectively control the upper and lower band edges of the antenna. The optimized antenna operates across 2.95–12.81 GHz for ^{3}. The characteristics of the proposed antenna are suitable for UWB wireless communication requiring low profile antennas.

Rapid development of wireless systems, a lot of concentration is being given for designing the UWB antennas, since they are the key elements to radiate and receive the signals [

The UWB antenna is a crucial component of such a system. The best choice for fabrication of ultrawideband antennas is on planar technology as it allows easly integration with microwave integrated circuits (MIC) and is light weight and relatively of low cost [

In this letter, a novel and very small CPW-fed UWB antenna design is proposed consisting of a fractal patch resembling specific structure. To extend the antenna’s impedance bandwidth the ground-plane is truncated at the middle with a pair of squared-shaped notches and rectangular notches are cut out from its sides. These notches affect the antenna’s upper and lower band edge frequencies, thus controlling the antennas impedance bandwidth. It is also shown that by increasing the number of fractals new resonances can be generated that enhance the antenna’s impedance bandwidth.

The configuration and parameters of CPW-fed fractal antenna is shown in Figure

Configuration of the proposed patch antenna with CPW-fed structure (Ant. II).

The fabricated CPW-fed antenna consists of a fractal patch with an array of fractal cells in the form similar to the branches of a tree. The antenna’s rectangular ground-plane is printed on the same side as the patch. To achieve a wider impedance bandwidth and hence realize UWB performance notches are cut out from its ground-plane at the sides and centers as shown in Figure

Different antenna configurations (Ant. I and Ant. II).

In this section, the parameters of the CPW-fed fractal antenna are discussed, and numerical and experimental results are presented. The antenna’s dimensions were determined through the optimization process. The effect of individual parameters was ascertained by changing the parameter in question and keeping all other parameters fixed. The distance between the ground and the fractal patch (

Simulated return-loss response as a function of antenna parameter

Simulated return-loss response of Ant. II with different ground configurations.

Return-loss response of Ant. II as a function of parameters

The proposed fractal patch is composed of repeating patterns. Increasing the iteration of the fractal patch leads to the generation of strong new resonances that improves the antenna’s impedance bandwidth. Antennas realized using one and two fractal iterations were fabricated on printed circuit board. The impedance bandwidth of the two antennas was measured using Agilent 8722ES S-parameter vector network analyzer (50 MHz–40 GHz).

Figure

Return-loss response of Ant. I and II.

The proposed antenna’s measured and simulated gain performance.

The measured radiation patterns of the proposed antenna at 6 and 10 GHz are shown in Figure

Measured radiation patterns of Ant. II at different frequencies.

A compact printed monopole antenna is presented consisting of a fractal radiating patch which is excited with a coplanar waveguide (CPW). It is shown that with the inclusion of two pairs of notches in the ground-plane, one can extend the antenna’s performance for ultrawideband applications. The antenna’s patch is composed of a definite number of fractal cells. The antenna’s parameters were investigated to fully determine the effect on its overall characteristics. Hence, the salient parameters from this analysis enabled the optimization of the antenna’s performance. Experimental and simulation results demonstrate that the fractal antenna exhibits desired ^{3}.

The authors declare that there is no conflict of interests regarding the publication of this paper.

This paper is the result of a research project approved by the research committee at Islamic Azad University, Urmia Branch, Urmia, Iran. The authors would like to thank Islamic Azad University, Urmia Branch, for its helpful support.