## 1 Introduction
In [31], the authors achieve tri-band notching at 3.40-3.65, 4.90-5.20, and 5.30-5.85 GHz by introducing two C-shaped slot resonators on the radiating patch and symmetric C-shaped slot resonator pair on the modified ground plane. By implementing the hook-shaped Defected Ground Structure (DGS) with the combination of slot resonators on the patch as well as ground plane, a triple band-notched band antenna is also reported in [32]. Similarly, a pair of CSRRs was used in [33] to achieve the triple band rejection in the frequency bands of 3.3-3.6, 5.1-5.4, and 5.7-5.9 GHz. In [34], they achieved the triple band notching in the frequency bands centered at 3.50, 5.50, and 8.10 GHz by introducing two rectangular complementary split ring resonators (RCSRRs) at the junction of the feed line, a meander-shaped stub, and an inverted U-shaped slot on the center of the radiating patch. Despite the recognition of different triple band-notched UWB antennas proposed in the literature, these designs have drawbacks in the sense of large dimensions, incomplete rejection of the interfering bands, and irregular and complicated resonator structures such as a combination of stubs and slot resonators. Also, triple band-notching is not enough to reject all the interfering bands as UWB have a broad spectrum, and other frequency bands such as INSAT (4.5-4.8 GHz), X-band satellite communication (7.2-7.65 GHz) and ITU 8-GHz (7.95-8.55 GHz) also fall. In this context, quadruple band-notched UWB antennas have been proposed to mitigate the potential interferences at four different bands. A quadruple band-notched UWB antenna has been proposed in [35] that has the capability to reject 2.3-2.9, 3.2-3.7, 5.2-5.89, and 8.06-8.8 GHz frequency bands. In [36] the authors designed a quad-notched UWB antenna on multilayer surfaces to reject the WiMAX, INSAT, lower and upper WLAN frequency bands. Similarly, in [37] the authors designed a quadruple band-notched antenna by the combination of C-shaped and Nested C-shaped slot resonators in the patch with the addition of U-shaped slot resonators in the ground plane. The antenna has the capability of rejecting 2.4-2.7 GHz, 3.42-3.97 GHz, 5.4-6.0 and 8-8.68 GHz, for notching WiMAX, WLAN, and ITU 8 GHz frequency bands. In [38], they designed a quad-notched UWB antenna for rejecting the WiMAX, INSAT, lower and upper WLAN bands and analyzed CSRR to CSRR coupling among them. After this work, researchers investigated the quintuple band-notching technique within the UWB frequency bands in order to further minimize the jamming effect within the UWB frequency band. In this regard, the first attempt to design quintuple band-notched antenna was carried out in [39]. Although the antenna successfully rejects the five narrow frequency bands, the reported antenna size is quite bulky (80 \(\times\) 80 mm\({}^{2}\)) for use in portable IoT applications. Similarly, the authors of [40; 41] proposed a quintuple band-notched UWB antenna which has a capability to reject 3.6, 5.2, 5.8, 7.5, and 8.3 GHz frequency bands. However, they have placed the five slot resonators in a very irregular pattern which makes it very tough to judge the exact position of the notches in their design. Also, the frequency response of the notched bands is not steep enough (with a Voltage Standing Wave Ratio (VSWR) between 2.2 and 3.8) to achieve desirable rejection performance. In this paper, we present a microstrip-line fed planar quintuple ultra-wideband (UWB) antenna using a combination of the rectangular complementary split ring resonator (RCSRR) and the rectangular split-ring resonator (RSRR) for rejecting the WiMAX, INSAT, lower WLAN, upper WLAN, and ITU 8 GHz frequency bands. At the beginning, a conventional stair cased structured reference UWB antenna is designed and fabricated to operate within the desired UWB frequency band.