# Planar UWB Monopole Antenna with Tri-Band Rejection Characteristics at 3.5/5.5/8 GHz
###### Abstract  
A triple band-notched ultrawide band (UWB) antenna is presented to avoid the interference of services working in the UWB band, such as WLAN, WiMAX and X-band satellite systems. The arc H-shaped slot on the radiating patch creates a low frequency notched band, while the other two band-notched bands are formed by cutting narrow slots on the ground plane. The presented antenna can operate on the ultrawide band efficiently and inhibit interference from three different kinds of narrow band communication systems. The simulation and measurement results show that the antenna has excellent band-notched function on the rejectband and almost omnidirectional radiation pattern on the passband. ultrawide band (UWB) antenna; triple band-notched; slots; planar monopole antenna 10.00.00. However, in these UWB antennas, most of them do not exceed two notched bands. There are fewer designs with three notched bands, which indicating that these dual band-notched UWB antennas may still be subject to interference from other narrow bands. In [18], a circular antenna with triple band-notched function at 2.45, 5.45, and 8 GHz was presented by using an inverted L-shaped slot and a ring on the circular patch. In [19], a UWB printed planar antenna with tri-band notched functions was presented. A notched band at 5.3-6.2 GHz was achieved by using a U-shaped slot defected ground structure. By cutting the H-shaped slot on the radiation patch, a notched band at 3.4-4.15 GHz for WiMAX and a notched band at 6.8-7.7 GHz for some X-band satellite communication systems were achieved. In [20], an antenna with band-notched function at 3.5, 4.5, 5.25, and 5.65 GHz was presented by using a complementary split ring resonator (CSRR) on a semicircular patch. In [21], by cutting four rectangular complementary split ring resonators (RCSRR) on the radiating patch and two rectangular open-loop resonators placed near the feedline, a smallest form factor UWB antenna with band-notched function at 3.5, 4.5, 5.25, 5.7 and 8.2 GHz was presented. In [22], by cutting two elliptic single complementary split ring resonators (ESCSRRs) on the radiating patch and placing two rectangular split-ring resonators near the feedline-patch junction of the antenna, a low profile microstrip fed compact UWB antenna with band-notched function at 3.54, 5.73 and 8.56 GHz was presented. In [23], an antenna with band-notched function at 3.55, 5.5, 7.8 GHz was presented by using a pair of modified capacitance loaded loop (MCLL) resonators. In [24], by cutting C-shaped slot and arc shaped slot on the radiating patch and using an annular strip above the radiating element, an antenna with band-notched function at 3.45, 5.5 and 7.4 GHz was presented. In [25], a compact UWB antenna with band-notched function at 3.5, 5.4 and 8.4 GHz was presented by cutting three square slots into the microstrip feedline. Although three notched bands were obtained, the completeness of the notched-band coverage was sacrificed in these designs. For instance, the antenna in [18] did not generate a notched band for WiMAX (3.3-3.7 GHz). The rejectband coverage for WLAN (5.15-5.825 GHz) was not complete in [19]. The antenna in [20,24] did not generate a notched band for X-band satellite applications operating near 8 GHz. In [21], almost no passband was available after the highest frequency notched band. The size of antenna in [22] was too large. In [23,25], the rejectband coverage for WiMAX was not complete. In this paper, a UWB antenna with a triple band-notched function is presented by cutting an arc H-shaped slot on the circular radiating patch and etching narrow slots on the ground plane. The presented antenna can operate within an ultrawide band from 3.1 GHz to about 10 GHz. At the same time, the antenna can completely reject three notched bands of 2.59-4.01 GHz, 4.73-6.11 GHz, 7.68-8.40 GHz. Thus, avoiding the interference from WLAN, WiMAX, and X-band satellite systems.