A New Class of Miniature Embedded Inverted-F Antennas (IFAs) for 2.4 GHz WLAN Application

Azad, M.Z.; Ali, Mohd. Hasan

doi:10.1109/tap.2006.880710

Cited by 28 publications

(18 citation statements)

References 28 publications

(27 reference statements)

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“…In this letter, a switched diversity scheme was considered for which one antenna is excited while the other remains open [6]. The envelope correlation coefficient is a measure that is used to determine the efficacy of the diversity system.…”

Section: B Space Diversitymentioning

confidence: 99%

“…The envelope correlation coefficient is a measure that is used to determine the efficacy of the diversity system. Radiation pattern data are used to determine the complex correlation coefficient [6], [11]. After which, is evaluated as .…”

Section: B Space Diversitymentioning

confidence: 99%

“…Although authors have earlier proposed diversity concepts for mobile handheld wireless terminals [3], [4], the challenges of designing and implementing multiple antennas within small portable devices have been very difficult to address. Nevertheless, progress in the realm of miniaturized antenna design has made it possible to look into diversity or smart antenna design at least at the higher frequencies, 1.8 GHz or higher [5], [6]. The specific absorption rate (SAR) characteristics of a smart antenna system were studied in [5], where two identical planar inverted-F antennas (PIFAs) were investigated.…”

mentioning

confidence: 99%

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A Miniature Spiral Diversity Antenna System With High Overall Gain Coverage and Low SAR

Sayem

Khan

Ali

2009

Antennas Wirel. Propag. Lett.

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Abstract-A miniature spiral diversity antenna system operating at 1.85 GHz is proposed. Two 10 mm 6.25 mm antennas were placed at two corners of a printed circuit board at a height of 7 mm from the ground plane. Each antenna achieves nearly 7% bandwidth within 6 dB return loss. The mutual coupling between the two antennas is less than 10 dB. The proposed diversity antenna scheme exhibits high overall gain performance in all three principal planes compared to a single antenna solution. Computed specific absorption rate (SAR) data against a specific anthropomorphic mannequin (SAM) phantom and a hand model show that the diversity antenna system induces low SAR compared to a single antenna.

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Section: B Space Diversitymentioning

confidence: 99%

Section: B Space Diversitymentioning

confidence: 99%

mentioning

confidence: 99%

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A Miniature Spiral Diversity Antenna System With High Overall Gain Coverage and Low SAR

Sayem

Khan

Ali

2009

Antennas Wirel. Propag. Lett.

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“…So it makes sense instead to design and use a miniaturized antenna with relatively low efficiency and then use an integrated LNA. Earlier researchers have shown that the Hilbert curve can be used to design miniaturized antennas [13]- [16] by dint of its longer current flow path within a specific surface area. In this communication an inverted-F antenna (IFA) is studied and designed using the Hilbert curve.…”

Section: Introductionmentioning

confidence: 99%

“…In this communication an inverted-F antenna (IFA) is studied and designed using the Hilbert curve. The antenna geometry is similar to the one described in our earlier work [16]. To design the antenna for implanted application at the GPS frequency of 1.575 GHz simulations were performed in HFSS 1 and XFDTD 2 (with anatomically based human head and body model).…”

Section: Introductionmentioning

confidence: 99%

A Miniature Implanted Inverted-F Antenna for GPS Application

Azad

Ali

2009

IEEE Trans. Antennas Propagat.

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Abstract-A miniature implanted Hilbert inverted-F antenna design at the 1.575 GHz global positioning system (GPS) frequency is proposed, which can be used to track the location of its user, e.g., the elderly with declining mental capacity (Alzheimer's disease). A detailed parametric study of the antenna design is performed by considering it to be implanted within a human muscle model. The effects of the substrate, superstrate, and the nearby muscle tissue on antenna performance are carefully investigated. A laboratory prototype of the antenna was built and tested within a muscle equivalent fluid indicating good VSWR performance. Finally the said antenna when placed within the tissue equivalent fluid was also tested to track GPS satellites with the help of a low noise amplifier (LNA). Such field measurements demonstrate that the antenna can easily lock into six or more satellites which are more than enough to determine the location of a person.

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Design of a compact antenna for Bluetooth application

Yoon

2008

Micro & Optical Tech Letters

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where rSub ϭ rSub Ј Ϫ j rSub Љ and Sub ϭ 1/ Sub are the equivalent relative permittivity and equivalent conductivity of the multilayer substrate formed by the silicon and the silicon dioxide. With these realistic parameter values, the agreement between measurements and simulations is very good, even for the phase of S 21 given in Figure 4(b). DISCUSSIONThe insertion losses have to be reduced so that this kind of filter can be integrated into front-ends for a few GHz operating frequencies. We have studied the origin of the filter insertion losses. They can be divided into three contributions: the CPW transmission line metallic losses, the varactors series resistance, and the silicon losses.The reduction of the CPW transmission line metallic losses could be carried out by enlarging the CPW central conductor width W 0 , and consequently the gap width G 0 , to keep the same characteristic impedance of the unloaded transmission line. Nevertheless, enlarging the gap width induces a greater penetration of electric field in the silicon substrate, thus potentially enlarging dielectric losses. Then the use of a high-resistivity silicon (HR Si) substrate or SOI substrate could allow minimizing the contribution of substrate losses. Finally, the varactors must be inserted inside the CPW gap so that the series resistance can be minimized.Considering the parameters given in Table 1 and a 465 fFcapacitance value C vmean of the varactors leading to filter mean cutoff frequency of 4.3 GHz, the contribution of each insertion losses source has been studied. Figure 5 shows that improved filter behaviors could be obtained considering the realistic parameters values listed as follows:The series resistance R s given by the manufacturer fixed to 2 ⍀ instead of 10 ⍀. In practice, this value could be obtained if the varactors were designed inside the CPW gap. A low-loss substrate corresponding to HR Si or SOI substrate ( Si ϭ 4000 ⍀ cm instead of 110 ⍀ cm). An enlarged CPW design to reduce conductor losses (W 0 ϭ 10 m and G 0 ϭ 95 m instead of W 0 ϭ 3 m and G 0 ϭ 34.5 m).These simulations show that considering a 2-⍀ series resistance compared with the actual manufactured filter allows to decrease the insertion loss by about 1.4 dB at 4.3 GHz ( S 21 ϭ Ϫ5.7 dB instead of Ϫ7.3 dB). If we consider this 2-⍀ series resistance on a HR Si ( Si ϭ 4000 ⍀ cm), the insertion loss at 4.3 GHz is S 21 ϭ Ϫ4.8 dB. Finally, by enlarging the CPW design on a HR Si, with varactors inserted inside the CPW gap (R s ϭ 2 ⍀), the insertion loss could be reduced by ϳ2.5 dB in the passband, leading to S 21 ϭ Ϫ2.3 dB at 4.3 GHz. CONCLUSIONA compact coplanar tunable low-pass filter, integrated on a lowresistivity standard silicon substrate, has been presented in this article. The performances of the filter are very interesting when compared with its ultra compact size. A Ϯ19% cutoff-frequency tuning around 4.3 GHz without any spurious peak until 30 GHz has been obtained. Insertion losses are mainly due to the conductor at low frequencies (1.5 dB). As explained earlier,...

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A New Class of Miniature Embedded Inverted-F Antennas (IFAs) for 2.4 GHz WLAN Application

Cited by 28 publications

References 28 publications

A Miniature Spiral Diversity Antenna System With High Overall Gain Coverage and Low SAR

A Miniature Spiral Diversity Antenna System With High Overall Gain Coverage and Low SAR

A Miniature Implanted Inverted-F Antenna for GPS Application

Design of a compact antenna for Bluetooth application

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