# A Compact Monopole Wideband Antenna Based on DGS
## 1 Introduction  
Monopole patch antennas have gained significant attention in recent years due to their compact size, ease of fabrication, and versatility in various communication applications. The introduction of defected ground structures (DGSs) has further enhanced the performance of these antennas by improving bandwidth and reducing electromagnetic interference. This study focuses on the design and simulation of a DGS-based monopole patch antenna. The choice of Taconic TLY substrate, characterized by a low dielectric constant and minimal loss tangent, supports efficient radiation characteristics. The incorporation of L-slot and circular slot segment configurations in the ground plane allows for effective ground defection, which is critical in enhancing the antenna's performance metrics. There are different bandwidth enhancement techniques for monopole patch antennas, such as integrating DGS with air-loaded patches, DGS with fractal patch structures, modifying the patch and/or applying slots and using partial ground plane or DGS, frequency reconfiguration using pin diodes, DGS-based monopole patch, using different feed techniques such as using tapered feed with tapered patches and coplanar waveguide (CPW) feed. These have been suggested by antenna designers in order to achieve wider bandwidth. In [1], a wide-bandwidth antenna DGS-integrated air-loaded wideband microstrip antenna for X- and KU-band is presented. The enhanced bandwidth is achieved by asimple and completely planar air-gap-loaded rectangular microstrip antenna integrated with a single shorting post and defected ground structures. This design has an impedance bandwidth ratio of 8.3-15.2 GHz. The suggested antenna's gain ranges from 5 to 6.5 dBi. By modifying and applying optimized slots to patch and partial grounding or using DGS, it results in increased bandwidth. For example, special shapes with rounded structures and various optimized slots in partial grounds, which play a major role in producing desired wideband characteristics [2]. This antenna has a bandwidth of 1.73 to 12.73 GHz and a gain of 4.47 dBi. By increasing the size of the patch and the DGS in it, it is possible to have a wideband antenna [3]. A miniaturized planar antenna with optimized slots and DGS is designed [4]. This antenna has a range of bandwidth from 5.75 to 12.86 GHz and a peak gain of 5.4 dB. In a similar manner, a circular patch antenna with rectangular slots and DGS for UWB multiband applications [5] has a dual bandwidth from 4.98 to 8.08 GHz and 11.49-20 GHz and a gain of 6.9 dBi. The other technique is by using a modified plus-shaped microstrip patch antenna with DGS for UWB applications [6]. By incorporating DGS, the ultra-wideband (UWB) is achieved with a bandwidth of 8.85 GHz 6.39 to 14.73 GHz, and the peak gain obtained is 3.79 dBi at 7.1 GHz and 5.75 dBi at 12.8 GHz. A slotted monopole patch antenna design for UWB wireless applications [7] is presented. This multi-slot patch antenna that is designed, optimized, and analyzed with a partially slotted ground plane for UWB wireless applications has a bandwidth of 3.15 to 10.79 GHz and a gain of 3.22 dBi. Wideband monopole patch antennas can be designed by slotting the patch [8; 9; 10]. DGS-based Koch fractal antennae for S- and C-band applications are designed for wide bandwidths [11]. In this antenna the radiator is miniaturized by using the fractal technique, and wideband is achieved with the help of the defected ground structure technique, and it has a bandwidth from 1.76 to 4.29 GHz and a peak gain of 4.06 dB. A compact 8-state frequency reconfigurable UWB antenna with a bandwidth of 2.82 GHz to 13.25 GHz and a gain of 5 dBi in [12]. Here, three PIN diodes are connected across the C-slots and inverted U-slot, and by controlling the on/off state of PIN diodes, realize notch reconfiguration. Defected ground structure-based monopole patch antennas are common to design wider band antennas [13; 14; 15; 16; 17; 18; 19; 20].