# A Compact Size Antenna for Extended UWB with WLAN Notch Band Stub
###### Abstract  
An ultra-wideband (UWB), geometrically simple, compact, and high-gain antenna with a WLAN notch band is presented for future wireless devices. The antenna is printed on the top side of the Rogers RT/Duroid 5880 substrate and has a small dimension of 10 mm \(\times\) 15 mm \(\times\) 0.254 mm. The primary radiator of the proposed coplanar waveguide-fed monopole antenna is comprised of a rectangular-shaped structure initially modified using a slot, and its bandwidth is further enhanced by loading a Y-shaped radiator. As a result, the antenna offers a -10 dB impedance matching bandwidth of 11.55 GHz ranging from 3-14.55 GHz, covering globally allocated C-, S-, and X-band applications. Afterward, another rectangular stub is loaded in the structure to mitigate the WLAN band from the UWB spectrum, and the final antenna offers a notched band spanning from 4.59 to 5.82 GHz. Moreover, to validate the simulated results, a hardware prototype is built and measured, which exhibits good agreement with the simulated results. Furthermore, the proposed work is compared to state-of-the-art antennas for similar applications to demonstrate its design significance, as it has a compact size, wider bandwidth, and stable gain characteristics. UWB antenna; compact antenna; notch-band antenna; WLAN band rejection +
Footnote †: journal: _Sciences_  
functionality. Therefore, a lot of research has been done in designing new antennas for UWB spectrum with notching characteristics. Since the 5 GHz band spectrum is widely used for a number of applications, there is a dire need to mitigate this band from the UWB region to minimize the interference with the UWB communication systems. Therefore, various UWB antenna systems in the literature [15] are focusing on efficient antenna systems offering low interference. Hence, to meet the requirement of present day UWB applications, UWB antennas should offer notch band functionality without sacrificing overall antenna performance in terms of bandwidth, gain, and stable radiation pattern [16; 17]. Several UWB antennas with WLAN notch band characteristics that have the advantages of compact electrical size have been widely investigated in the literature [18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30]. For instance, a circular patch antenna that has a balanced notch band feature with a common mode suppression is presented in [18]. A stub-loaded circular patch-based antenna was designed to achieve UWB mode. Afterward, a bandpass filter was designed in such a way that the resonator is judiciously fed, resulting in a common notch band behavior. However, due to the utilization of a filter, the overall size of the antenna gets increased, and the optimized antenna offers a physical size of 29.38 mm \(\times\) 28.25 mm. Likewise, a circular-shaped monopole antenna is designed in [26] to achieve wide operational mode ranges from 2.8-12 GHz, while an enhanced mushroom-like modified Electromagnetic Band Gap (EBG) structure is utilized to notch the desired band. However, the reported antenna has several drawbacks, including structural complexity and a larger physical dimension of 40 mm \(\times\) 50 mm. A rectangular-shaped quarter-wave monopole antenna was modified using two consecutive iterations of slots to design a modified W-shaped fractal antenna for UWB applications [27]. Additionally, a pair of two inverted L-shaped open-ended stubs were loaded with a ground plane to achieve notch band functionality. The resulting antenna operates from 3-12 GHz, a notched band of 5.2-5.8 GHz, and a set back of a large overall size of 31 mm \(\times\) 27 mm. On the other hand, a multi-layered Artificial Magnetic Conductor (AMC) loaded UWB antenna is presented in [28]. At first, a rectangular monopole was modified using truncated corners to widen the bandwidth, then two modified U-shaped slots were etched to achieve a notch band, and finally, an AMC was loaded to enhance the performance of the antenna.