Slotted Printed Monopole UWB Antennas with Tunable Rejection Bands for WLAN/WiMAX and X-Band Coexistence

Abstract

Four versions of the compact hexagonal-shaped monopole printed antennas for UWB applications are presented. The first proposed antenna has an impedance bandwidth of 127.48% (3.1 GHz to 14 GHz), which satisfies the bandwidth for ultra-wideband communication systems. To reduce the foreseen co-channel interference with WLAN (5.2 GHz) and X-Band systems (10 GHz), the second and third antennas type were generated by embedding hexagonal slot on the top of the radiating patch. The integration of the half and full hexagonal slots created notched bands that potentially filtered out the sources of interference, but were static in nature. Therefore, a fourth antenna type with tunable-notched bands was designed by adding a varactor diode at an appropriate location within the slot. The fourth antenna type is a dual-notch that was electronically and simultaneously tuned from 3.2 GHz to 5.1 GHz and from 7.25 GHz up to 9.9 GHz by varying the bias voltages across the varactor. The prototypes of the four antenna versions were successfully fabricated and tested. The measured results have good agreement with the simulated results.

Design of UWB microstrip patch antenna with variable band notched characteristics

“…Usually, UWB is performing with wide operating bandwidth, while designing a UWB antenna has some challenges like achieving large impedance bandwidth, low reflection coefficient, significant radiation pattern and space limitations. There are several narrowband applications within the UWB [2-6] like 3.3 GHz to 3.7 GHz of WiMAX [7], 3.3 to 3.8 GHz of C-band for ASEAN [8], lower frequency band (4.5 − 5.5 GHz) for 5G (fifth generation) applications [9], 5.15 GHz to 5.35 GHz and 5.725 to 5.825 GHz of WLAN [10], 7.25 to 7.75 GHz of satellite downlink communication for International Telecommunication Union (ITU) [11], 7.725 to 8.275 GHz of X-band [12] and so on. To improve the 358 performance of a planar UWB antenna, several methods can be applied like different patch shapes, partial ground, inset-fed, defected ground structure (DGS), coplanar waveguide (CPW) and various type of slots on the radiating patch [12,[13][14][15][16][17][18][19].…”

“…There are several narrowband applications within the UWB [2-6] like 3.3 GHz to 3.7 GHz of WiMAX [7], 3.3 to 3.8 GHz of C-band for ASEAN [8], lower frequency band (4.5 − 5.5 GHz) for 5G (fifth generation) applications [9], 5.15 GHz to 5.35 GHz and 5.725 to 5.825 GHz of WLAN [10], 7.25 to 7.75 GHz of satellite downlink communication for International Telecommunication Union (ITU) [11], 7.725 to 8.275 GHz of X-band [12] and so on. To improve the 358 performance of a planar UWB antenna, several methods can be applied like different patch shapes, partial ground, inset-fed, defected ground structure (DGS), coplanar waveguide (CPW) and various type of slots on the radiating patch [12,[13][14][15][16][17][18][19]. It is found from the literature that in most of the cases, the band-notched characteristics have been achieved by different slots on the radiating patch and ground plane [15], while, it is easy to achieve UWB with partial ground plane [20,21].…”

Compact Uwb Antenna With Tunable Band-Notch Characteristics Using Varactor Diode

“…Therefore, it is necessary to design a tunable band-notch UWB antenna to adapt to an unstable environment. Several reconfigurable band-notched UWB antennas have been reported, and the frequency can be continuously tuned or reconfigurable by using a varactor diode, a PIN diode, and a capacitor [18][19][20][21][22][23][24][25][26][27]. In [18], a single tunable band-notch frequency 4.62-5.83 GHz is achieved by using a varactor in a heart-shaped UWB antenna on a 30 × 40 mm 2 substrate.…”

“…In [20], dual tunable band-notch frequencies 3.5-4.5 GHz and 5.3-6.05 GHz are achieved by using a varactor on a 34 × 27 mm 2 substrate. A hexagonal-shape UWB antenna on a 30 × 30 mm 2 substrate is designed, and tunable band notch frequencies are achieved by using varactor from 3.1-5.1 GHz and 7.25-9.9 GHz, respectively [21]. In [22], a CPW-fed UWB antenna on a 30 × 31 mm 2 substrate has been reported, and tunable frequency from 3 to 4 GHz is achieved by using a capacitor.…”

“…The antenna structures in [18][19][20][21][22][23][24][25][26][27], with single or dual tunable-band notched behavior employ a varactor, a PIN diode, and/or a capacitor. However, these antennas have large dimensions; some antennas cannot be tuned continuously and do not have appropriate tuned band notch capability.…”