###### Abstract  
In this research article, a single-fed dual-band circular polarized (CP) dielectric resonator antenna (DRA) for dual-function communication, such as GPS and WLAN, was made. Initially, the proposed design process was initiated by designing a linearly polarized singly fed-DRA. To attain CP fields, the cross-shape conformal metal strip was optimized to excite the fundamental and the high-order mode in the two frequency bands. The metallic strip (parasitic) was utilized on top of the rectangular DRA to improve and widen the impedance and axial ratio (AR) bandwidth. This step led to a 2.73% improvement on the lower band and an impact of 6.5% on the upper band while on the other side a significant improvement was witnessed in the AR bandwidth in both frequency bands. A prototype was designed and fabricated in order to validate its operations. The measurement outcomes of the proposed antennas authenticated wideband impedance bandwidths of 6.4% and 25.26%, and 3-dB axial ratios (AR) of 21.26% and 27.82% respectively. The prototype is a decent candidate for a global positioning system (GPS) and wireless local area network (WLAN). s 2022 2022019 May  
Circular polarized antennas are beneficial in several areas, including mobile, radar, satellite, and other communications systems, due to the advantages of mitigating polarization discrepancy, suppressing multiple multipath reflections/different types of interventions, improving channel capacity, and system reliability. As a result, circularly polarized DRAs may readily control the limitations imposed by their LP counterparts [4, 5, 6, 7, 8]. Circular polarization in an antenna has been achieved using a variety of approaches, which can be split into two categories: single-fed and multiple-fed systems. Though multiple-point-fed models required more room to create the requisite antenna, they can attain wider bandwidths than single-fed devices [9]. Putting hybrid couplers underneath the DRAs is one way for shrinking the size of the circularly polarized antenna. This procedure gives a significant 3-dB axial ratio (AR) and Impedance matching (S11) bandwidths with a small-scale footprint [10]. Modifying DR shapes such as stair-shape [11], rotating stair [12], trapezoidal [13], inverted sigmoid shape [14], parasitic metal strips on sidewalls or on adjoining metallic plates [15], and diagonally inclined slits with DR [16] are other techniques to extend bandwidths. The geometry of DRA was altered in an azimuthal direction occasionally in [16] to disintegrate tangential electric fields of boundaries orthogonally. Circularly polarized waves with an adequate AR bandwidth were created using a single-point feed. In contrast to [17], the same approach was used in [18] with an inclined slot and microstrip, resulting in a narrow 3 dB AR bandwidth. In [19], changing the geometrical shape of a trapezoidal DRA with a notch at its top enhances the Impedance matching bandwidth, and as a result, a noteworthy 3-dB AR ratio bandwidth has been achieved with the use of an inclined slot. In [20], a DRA has an aperture-coupled stair shape, which is made up of two rotatable rectangular DR. In dual bands, this change results in a wide impedance and AR bandwidth. Printing a conducting loop on DRA can produce circularly polarized waves, resulting in a wider AR bandwidth [21]. The strips on the DRA sidewall not only degenerate two orthogonal modes with a small AR bandwidth, but they were also wonderfully shrunk [22]. Ref. [23] demonstrated that with this approach, 3-dB AR bandwidth can be achieved in MIMO DRAs. The bandwidth was boosted by placing DRA without a gap, which results in a higher length to width (L/W) aspect ratio. Furthermore, to increase Impedance matching and AR bandwidth, the approach [24, 25] can be used with vertical metallic plates across the DR. Another way to increase bandwidth is to use slanted holes on the diagonal and sidewalls of DR [26] to achieve CP waves. It is important to remember that each of the processes listed above has its own set of fabrication issues.