scholarly journals New compact multiband inverted-L frequency reconfigurable antenna for cognitive radio applications

Author(s):  
Abdullah Ali Jabber ◽  
Raad H. Thaher

This paper presents, new compact and multiband frequency reconfigurable antenna for cognitive radio applications. A UWB sensing and reconfigurable communicating antennas are contained at the same substrate, where the UWB sensing antenna is an elliptical printed monopole antenna operates on frequency band from (2.65-22.112) GHz which can cover the UWB frequency band from 3.1 to 10.6 GHz, while the communicating antenna is an inverted-L frequency reconfigurable antenna operates on three bands of 1.49 GHz, 5.58 GHz, and 5.6 GHz under (S11 ≤ -10 dB) with a fractional bandwidth of 5.872%, 6.02%, and 6.05% respectively. The proposed antenna used to operate in two modes one for cognitive radio applications to cover WLAN applications at 5.5 GHz and 5.6 GHz and the second mode for wireless Ethernet, GPS synchronization, and Internet of Things that Matter (IoTtM) at 1.49 GHz. The frequency reconfigurability is obtained by using only a single RF switch (PIN diode) for changing the operating frequency. The antenna overall dimensions are 72 x 36 x 1.6 mm<sup>3</sup> printed on an FR-4 epoxy substrate of 4.3 relative-permittivity, loss tangent tan (δ) = 0.002 and 50 Ω micro stripline feed. The obtained simulated gain is ranging from 1.35 to 4.132 dBi. The S11 and isolation (S12) between the two antennas are under -20 dB and -17 dB respectively at the resonant frequencies.

2020 ◽  
Vol 9 (1) ◽  
pp. 212-220
Author(s):  
Abdullah Ali Jabber ◽  
Raad H. Thaher

This paper presents, new compact tri-band and broadband frequency reconfigurable antenna for cognitive radio applications. The proposed antenna consists of an Ultrawideband sensing antenna and reconfigurable communicating antenna at the same substrate. The sensing antenna is a UWB printed elliptical monopole antenna operates at frequency band from 2.72 to 23.8 GHz which can cover the entire UWB frequency band from 3.1 to 10.6 GHz and cover the broadband up to 20 GHz. The communicating antenna is a T-shaped frequency reconfigurable antenna operates on three bands of 7.925 GHz, 13.16 GHz, and 14.48 GHz under (S11≤-10 dB) with a fractional bandwidth of 14.55%, 6.2%, and 3.3% respectively. The proposed antenna used to operate in two modes one for cognitive radio applications to cover WiMAX, land, Fixed and Mobile satellite, Radar, and broadband applications. The frequency reconfigurability is obtained by using only one RF switch (PIN diode) for changing the operating frequency. The antenna overall dimensions are 42x30x1.6 mm3 printed on an FR-4 epoxy substrate with relative dielectric constant εr=4.3, loss tangent tan (δ)=0.002 and 50Ω microstrip line feed. The maximum obtained simulated gain is 8.5 dB at 13.16 GHz. The S11 is under -20 dB and coupling between the two antennas is less than -15 dB at the resonant frequencies.


2018 ◽  
Vol 10 (12) ◽  
pp. 122 ◽  
Author(s):  
Zubin Chen ◽  
Baijun Lu ◽  
Yanzhou Zhu ◽  
Hao Lv

In this paper, a printed monopole antenna design for WiMAX/WLAN applications in cable-free self-positioning seismograph nodes is proposed. Great improvements were achieved in miniaturizing the antenna and in widening the narrow bandwidth of the high-frequency band. The antenna was fed by a microstrip gradient line and consisted of a triangle, an inverted-F shape, and an M-shaped structure, which was rotated 90° counterclockwise to form a surface-radiating patch. This structure effectively widened the operating bandwidth of the antenna. Excitation led to the generation of two impedance bands of 2.39–2.49 and 4.26–7.99 GHz for a voltage standing wave ratio of less than 2. The two impedance bandwidths were 100 MHz, i.e., 4.08% relative to the center frequency of 2.45 GHz, and 3730 MHz, i.e., 64.31% relative to the center frequency of 5.80 GHz, covering the WiMAX high-frequency band (5.25–5.85 GHz) and the WLAN band (2.4/5.2/5.8). This article describes the design details of the antenna and presents the results of both simulations and experiments that show good agreement. The proposed antenna meets the field-work requirements of cable-less seismograph nodes.


Frequenz ◽  
2016 ◽  
Vol 70 (9-10) ◽  
Author(s):  
Xiaolin Yang ◽  
Ziliang Yu ◽  
Zheng Wu ◽  
Huajiao Shen

AbstractIn this paper, we present a novel frequency reconfigurable antenna which could be easily operate in a single notched-band (WiMAX (3.3–3.6 GHz)) UWB frequency band, another single notched-band (WLAN (5–6 GHz)) UWB frequency band and the dual band-notched UWB frequency band (the stopband covers the WiMAX (3.3–3.6 GHz) and WLAN (5–6 GHz)). The reconfigurability is achieved by changing the states of PIN diodes. The simulated results are in agreement well with the measured results. And the measured patterns are slightly changed with antenna reconfiguration. The proposed antenna is a good candidate for various UWB applications.


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