Enhancing the Performance of Handset Antennas by Means of Groundplane Design
06 Mar 2006-pp 29-32
TL;DR: The present paper shows a conventional design for dual-band operation and how it can be improved for a quad-band design through the FracPlane technique, which encapsulates both basic shaping of a groundplane to a more sophisticated space-filling and/or multilevel design for further size reduction and multi-band performance enhancement.
Abstract: INTRODUCTION Mobile devices are in a constant state of evolution given the increasing features and frequencies available worldwide. Today, global handset functionality is becoming an important consideration influencing customer purchasing habits. Industry dynamics have increased the drive for smaller and multi-functional wireless devices. Antenna technology has played a key role in influencing the end form factor of these mobile devices because without the antenna the device is not wireless. The present paper shows a conventional design for dual-band operation (GSM900-DCS1800) and how it can be improved for a quad-band design (GSM850-GSM900-DCS1800-DCS1900) through the FracPlane technique. This technique encapsulates both basic shaping of a groundplane to a more sophisticated space-filling and/or multilevel design for further size reduction and multi-band performance enhancement [1,4].
Citations
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TL;DR: In this article, a multiband handset antenna combining a PIFA and multiple slots on a ground plane is presented, and it is shown by means of simulations that the slots on the ground plane have a double function: to tune ground plane resonance at low frequencies and to act as parasitic radiators at high frequencies.
Abstract: A multiband handset antenna combining a PIFA and multiple slots on a ground plane is presented. It is shown by means of simulations that the slots on the ground plane have a double function: to tune the ground plane resonance at low frequencies (f ? 900 MHz) and to act as parasitic radiators at high frequencies (f ? 1800 MHz). A prototype is designed and built featuring a behavior suitable for low frequencies (GSM850 and GSM900) and for high frequencies spanning from DCS1800 to Bluetooth, and including, for instance, PCS1900, UMTS2000, and other possible systems. Reflection coefficient, efficiency, and radiation patterns are measured and compared with a design without slots to prove the advantages of the slotted ground plane. The component effect is investigated to determine critical areas where the placement is not recommended. Besides, the effect of the slot of the ground plane on SAR is investigated, by discussing the effect of the ground plane and slot modes for two phone positions. The total antenna volume of the proposed design is 40 × 15 × 6 mm3.
225 citations
Cites background or methods from "Enhancing the Performance of Handse..."
...The main improvement of the proposed design over the design presented in [10] is the addition of slot #2....
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...Another example of an antenna design that uses a slotted ground plane is found in [10], where it is used to improve a conventional design for a dual-band...
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...Beginning from a reference antenna design proposed in [10]...
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...Simulated reflection coefficient of the proposed multiband antenna in comparison with those presented in [10] (Quad-band and Dual-band PIFA)....
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...In comparison with the reference antenna design of [10], the antenna presented here has two new slots in its PCB, namely slots #2 and #3....
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TL;DR: A description of the evolution of wireless handheld devices, regulations, challenges in today’s smartphones, and handset characterization is reviewed and recent advances in antenna technology for wireless handheld or portable devices are presented.
Abstract: The constant evolution of wireless handheld devices together with the apparition of multiple wireless communication systems fosters the antenna community to design new radiating and measurements systems capable of satisfying the market demands. It is an object of the present paper to provide an overview of the evolution that wireless handheld technology has experienced in the last years. In this sense, a description of the evolution of wireless handheld devices, regulations, challenges in today’s smartphones, and handset characterization is reviewed. Finally, recent advances in antenna technology for wireless handheld or portable devices are presented.
140 citations
Cites background from "Enhancing the Performance of Handse..."
...Nevertheless, the ground plane is progressively acquiring relevance since several studies have demonstrated its strong contribution to the radiation properties [77–90]....
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TL;DR: In this paper, a PIFA-based handset antenna technique combining a parallel excitation of the PIFA and a slot is presented, where the number of frequency bands is given by the sum of bands given per each radiator which can be controlled independently.
Abstract: A handset antenna technique combining a parallel excitation of a PIFA and a slot is presented. The number of frequency bands is given by the sum of bands given per each radiator which can be controlled independently. Component interaction (battery, display, and speaker) is analyzed to determine the best place to mitigate performance degradation. Finally, a concept featuring a small footprint (39 × 11 mm2) and low profile (2 mm) is proposed for multiband operation.
137 citations
Cites methods from "Enhancing the Performance of Handse..."
...[20]–[23] a similar design is proposed using a slot underneath...
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Patent•
15 Mar 2006
TL;DR: In this article, the ground plane is partially covered with an insulating material and the connecting means are given by a part of the ground planes which is not covered by any insulating materials.
Abstract: A wireless device includes a ground plane with at least two portions. On each of the at least two portions at least one connecting means is provided. The two connecting means are connected with an electric component for connecting the at least two portions of the ground plane. The ground plane is partially covered with an insulating material and the connecting means are given by a part of the ground plane which is not covered by any insulating material.
97 citations
TL;DR: A promising standard solution for a radiating system capable to operate in the main communication standards GSM850, GSM900, DCS, PCS and UMTS is provided with a volume reduction factor around 20.
Abstract: The increasing demand for multifunctional wireless devices has fostered the need to reduce the space devoted to the antenna in order to favor the integration of multiple and new functionalities. This fact becomes a challenge for the handset antenna designers who have to develop antennas capable of providing multi-band operation constrained by physical limitations. This proposal consists in a radiating system capable of providing multi-band operation without the need of an antenna element, by properly exciting the efficient radiation modes associated to the ground plane structure. In this sense, the typical volume devoted to a handset antenna is reduced by a factor of 20. The electrical model approximation of the radiating structure leads to the radiofrequency system design able to provide multi-band operation. The feasibility of the proposal has been tested by electromagnetic simulations as well as by experimental measurements regarding the main antenna parameters: reflection coefficient, efficiency, and radiation patterns. Furthermore, the human head interaction concerning biological compatibility in terms of SAR (Specific absorption rate) has been measured and a solution for its reduction is presented. As a result, a promising standard solution for a radiating system capable to operate in the main communication standards GSM850, GSM900, DCS, PCS and UMTS is provided with a volume reduction factor around 20.
97 citations
Cites background from "Enhancing the Performance of Handse..."
...Similar proposals are found in [9]–[14] where a slot is used for tuning the resonant mode to lower frequencies by providing a longer current path, whereas in [15] the resonant mode is tuned to the high fre-...
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References
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TL;DR: In this paper, the performance of the mobile phone handset antenna-chassis combination is analyzed based on an approximate decomposition of the waves on the structure into two resonant wavemodes: the antenna-element wavemode and the chassis wavemode.
Abstract: The performance of the mobile phone handset antenna-chassis combination is analyzed based on an approximate decomposition of the waves on the structure into two resonant wavemodes: the antenna-element wavemode and the chassis wavemode. A double resonator equivalent circuit model is presented and used to estimate the impedance bandwidth and the respective distributions of radiation losses with typical parameter values at 900 and 1800 MHz. It is noticed that at 900 MHz, the radiation losses of the antenna element wavemode represent typically less than 10% of the total power. Thus, the antenna element works mainly as a matching element, which couples to the low-Q resonant wavemode of the chassis. At 1800 MHz, the contribution of the antenna element wavemode is larger. By enhancing the coupling and by tuning the chassis resonance, it is possible to obtain an impedance bandwidth of over 50% (6 dB return loss) at both at 900 and 1800 MHz. The results given by the equivalent circuit study are fully supported by those of three-dimensional phone-model simulations, including calculation of the SAR and efficiency values. In prototyping, the 6 dB bandwidth of 5.5% was obtained at 980 MHz with a nonradiating coupling element with a volume of 1.6 cm/sup 3/ on a 120 mm long chassis.
500 citations
TL;DR: The pattern averaging gain (PAG) method to estimate the average gain of mobile antennas in a multipath propagation environment is proposed and the antenna configuration with the PIFA element mounted on the lateral side of the radio case is found to be most suitable for portable radio units.
Abstract: The pattern averaging gain (PAG) method to estimate the average gain of mobile antennas in a multipath propagation environment is proposed. By using this method and a wire-grid model, the radiation characteristics of the planar inverted F antenna (PIFA) mounted on a portable radio case is analyzed. In particular, the variation of the antenna gain with the radio case dimensions and inclination angle of the radio case during operation is clarified. Also, the effect on antenna patterns of the operator holding the portable radio is experimentally investigated. Based on this analysis, the antenna configuration with the PIFA element mounted on the lateral side of the radio case is found to be most suitable for portable radio units. In addition, an appropriate selection of the radio case dimensions is found to result in further improvements in the antenna bandwidth.
239 citations
TL;DR: In this paper, a new idea of increasing operational bandwidth of a compact planar inverted F antenna (PIFA) by introducing open-end slots in the ground plane under the radiating patch is described.
Abstract: This letter describes a new idea of increasing operational bandwidth of a compact planar inverted F antenna (PIFA) by introducing open-end slots in the ground plane under the radiating patch. The slots are not in the way of active modules of a wireless transceiver and thus the proposed antenna size reduction method is attractive from the point of view of practical implementation.
196 citations
"Enhancing the Performance of Handse..." refers background in this paper
...The present paper shows a conventional design for dual-band operation (GSM900-DCS1800) and how it can be improved for a quad-band design (GSM850-GSM900-DCS1800-DCS1900) through the FracPlane® technique....
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...In this sense, this paper shows how to handle the PCB in order to obtain not only broad bandwidth antenna at low frequencies to cover the GSM850-GSM900 spectrum but also at high frequencies DCS-PCS....
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...This represents an interesting finding for multiband mobile handset antennas covering several services such as GSM850-GSM900 [8]....
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TL;DR: In this paper, a small H-shaped microstrip patch antenna (MPA) with enhanced bandwidth is presented, where a stacked patch configuration is proposed to increase the narrow bandwidth, radiation efficiency and directivity.
Abstract: A small H-shaped microstrip patch antenna (MPA) with enhanced bandwidth is presented. The H-shaped antenna is first studied by a transmission line model and then is fully analyzed with a MoM code. A stacked patch configuration is proposed to increase the narrow bandwidth, radiation efficiency and directivity. The stacked H-shaped MPA is studied using Chu's fundamental limit for electrically small antennas.
106 citations
TL;DR: In this article, significant effects of groundplane dimensions on the impedance bandwidth of a planar inverted-F antenna for a UMTS (1920-2170 MHz) mobile handset are presented.
Abstract: Significant effects of ground-plane dimensions on the impedance bandwidth of a planar inverted-F antenna for a UMTS (1920–2170 MHz) mobile handset are presented. Experimental results show that, by varying the ground-plane length, the antenna studied can have an impedance bandwidth (10 dB return-loss bandwidth) varying from about 150 to 490 MHz, a variation of more than 300%. Similar behavior has also been observed for the case of varying the ground-plane width. Details of the experimental results are presented and discussed. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 249–251, 2002.
96 citations
"Enhancing the Performance of Handse..." refers background in this paper
...Depending on the dimensions of the groundplane, different results may be obtained [1,6,7]....
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