Systematic Design of UWB Monopole Antennas With Stable Omnidirectional Radiation Pattern

Abstract

This letter proposes a simple design approach to gain stable omnidirectional radiation pattern in printed ultrawideband (UWB) antennas. Monitoring of the current distributions in different frequencies shows that a combination of standing and traveling modes exists on the antenna. By determining the dominant mode at higher and lower frequencies, the corresponding optimum size of antenna that guarantees a stable omnidirectional radiation pattern and a good return loss is obtained. Using the proposed method, two compact antennas with circular ground and miniaturized fractal ground are designed. Simulation and measurement results show a good impedance matching and an excellent omnidirectional radiation pattern for proposed antennas.Index Terms-Monopole antenna, omnidirectional, pattern stability factor (PSF), radiation mechanism, ultrawideband (UWB).

A Compact Mimo/Diversity Antenna With Wlan Band-Notch Characteristics for Portable Uwb Applications

“…The introduction of the fractal slot helps to achieve the wideband performance as well as stable radiation patterns at higher frequencies [17]. The iteration wise generation of the fractal slot is presented in Figure 2.…”

A Novel Frequency Reconfigurable Monopole Antenna With Switchable Characteristics Between Band-Notched Uwb and Wlan Applications

“…In [18], two V-shaped slots are inserted in the ground plane structure to provide one more resonance, and two more resonances have been discussed. The impedance bandwidth enhancement with rectangular, circular and fractal DGSs has also been proposed in [19]. In order to improve impedance bandwidth, the upper edge of the ground plane is shaped using two rectangular slots of size 0.25 × 6 mm 2 and 0.25 × 4 mm 2 as shown in Fig.…”

A Novel Rectangular Ring Planar Monopole Antennas for Ultra-Wideband Applications

“…A microstrip UWB antenna is presented in [8] with size of 34 mm×36 mm×1.6 mm, operated only from 4.6 GHz to 9.6 GHz. The detailed comparison with other antennas presented in [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] is given in Table 1. The proposed rectangular ring ultra-wideband planar monopole antenna has a size of 28 mm× 26 mm×1.525 mm with impedance bandwidth of 124.16% and gain varying between 1.89 dBi to 5.2 dBi.…”

“…Only designs in [9,16], and [21] have smaller areas than the proposed antenna, but with larger volumes, lower gains, and smaller bandwidths. [7] 30 × 34 × 12 9 1020 67.7 [8] 36 × 34 × 1.6 4.95 1224 70.4 [9] 15 × 33 × 5 4.15 495 120 [10] 100 × 100 × 0.762 5 10000 88.8 [11] 50 × 50 × 0.5 5 2500 70.7 [12] 32 × 35 × 1.5 5.9 1120 107.2 [13] 60 × 30 × 1.6 2.2 1800 142 [14] 32 × 40 × 0.76 3 1280 109.4 [15] 106 × 85 × 0.8 5 9010 163.6 [16] 25 × 28.5 × 1.27 --712.5 80.5 [17] 46.13 × 34.9 × 0.43 --1608.8 109.4 [18] 51.2 × 62 × 0.76 3 3174 85.7 [19] 57 × 77 × 0.76 6.98 4389 109.4 [20] 28.5 × 28 × 0.8 2.99 798 110. [21] 18 × 36 × 11 3.5 648 110 [22] 28 × 29 × …”