New Simple Flower Shaped Reconfigurable Band-Notched Uwb Antenna Using Single Varactor Diode

Abstract

Abstract-In this paper, a new flower-shaped microstrip line feed reconfigurable band-notched UWB monopole antenna using single varactor diode is introduced and fabricated. Different notch frequencies can be obtained using different capacitance values. The effect of changing the varactor position is also examined. The flower shape is first optimized to obtain UWB characteristics. Then, a slot is made in the microstrip line to be loaded later with a single varactor diode. A wide range of notch frequencies can be obtained using this simple configuration which covers most of the narrow band coexistence systems. The notch frequency can be lower by increasing the capacitance value. The notch frequency covers the WLAN band when C = 0.8 pF and covers the WiMAX band when the capacitance is changed to 0.7 pF for the same antenna configuration and varactor position. Two prototypes of the proposed antenna using two different single capacitor elements with capacitances 0.6 pF and 1.5 pF are fabricated, and their reflection characteristics are measured and compared with the simulated ones. Notch frequencies at 6.1 GHz and 4.3 GHz are obtained respectively in both simulated and measured antenna structures. The proposed antenna has a directive radiation pattern in E-plane and omnidirectional pattern in Hplane. Also, the gain is suppressed in the notched frequencies. The group delay is nearly stable in the UWB frequency range with very little variations, but it is distorted sharply at the notch frequencies. So, the proposed antenna is a good candidate for the modern UWB systems.

Tunable Triple Band-Notched Uwb Antenna Using Single Ebg and Varactor Diode

“…Various techniques are employed in band-notched antennas to produce notches at specific frequency of interest. However, these band notches are achieved by etching slots on radiating elements, using resonators or with multi-parasitic elements around the feed line [7][8][9][10][11][12][13][14][15][16][19][20][21][22][23][24][25][26][27][28][29][30][31]. In order to achieve multiple band-notches, UWB antennas should not only make effective use of the space around the radiating patch but also be able to minimize coupling effects with less parasitic elements near the feed line.…”

“…12(a) and (b), respectively. Previously, various reconfigurable band-notched antennas using more active devices such as capacitors and varactors have been reported in [19][20][21][22][23][24][25][26][27][28][29][30][31]. In [19], open loop resonators (OLRs) are used around the feed line of antenna to produce single band-notch, and the antenna is tuned from 5.1 to 5.9 GHz using two varactors embedded in the OLRs.…”

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 [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. A flower-shape UWB antenna on a 42 × 50 mm 2 substrate offers tunable band-notch frequency from 6.1 to 4.3 GHz by using a varactor and a capacitor [23]. A triangular-shaped UWB antenna [24], on a 40 × 30 mm 2 substrate, offers tunable notch frequency at 5.3 and 3.4 GHz by using PIN diode and 5.57 and 3.52 GHz by using an ideal switch.…”

“…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.…”