Bandwidth‐enhanced internal PIFA with a coupling feed for quad‐band operation in the mobile phone

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conical beam patterns was characterized and verified with measurements and shown to have acceptable axial ratio. The present antenna design can be used as a good candidate for applications in short-range wireless communication systems, particularly wireless sensor networks, where the conical beam will give advantages of energy saving and reduced co-channel interference. Other applications could include indoor WLAN antennas for mounting on ceilings or other horizontal surfaces. Recently, a variety of multiband loop antennas for wireless wide area network (WWAN) operation in the mobile phone have been demonstrated [1][2][3][4][5][6][7]. These loop antennas are attractive for mobile phone applications in part, because their excited surface current paths are in a closed form, which is different from the conventional mobile phone antennas such as the monopoles or planar inverted-F antennas (PIFAs), whose excited surface current paths are in an open form [8]. Hence, the possible coupling between the loop antenna and the system ground plane of the mobile phone can be much smaller than that of the conventional mobile phone antennas. In this case, the variations in the dimensions of the system ground plane will show smaller effects on the performances of the loop antenna. For the reported multiband loop antennas for mobile phone applications [1][2][3][4][5][6][7], most of them use a direct feed, and the obtained operating bands cover several of the GSM850 (824 -894 MHz), GSM900 (890 -960 MHz), GSM1800 (1710 -1880 MHz), GSM1900 (1850 -1990, and UMTS (1920( -2170 bands for WWAN operation. In this article, we present a surfacemount loop antenna with a capacitively coupled feed for achieving seven-band operation covering all the five operating bands for WWAN operation, the 2.4-GHz band (2400 -2484 MHz) for wireless local area network (WLAN) operation, and the 2.5-GHz band (2500 -2690 MHz) for worldwide interoperability for microwave access (WiMAX) operation [9 -15]. That is, WWAN/WLAN/ WiMAX multinetwork operation can be achieved for the proposed antenna. SEVEN-BAND SURFACE-MOUNT LOOP ANTENNA WITH A CAPACITIVELY COUPLED FEED FOR MOBILE PHONE APPLICATIONThe capacitively coupled feed applied in the proposed loop antenna comprises a coupling strip and a tuning strip, which is different from the conventional capacitive feed that has been studied for internal mobile phone antennas [5, 16 -18]. The conventional capacitive feed mainly has a coupling strip or coupling portion only, and with the capacitive feed, widened bandwidth in the lower band (900 MHz band) of the antenna [16] or reduced size of the antenna [17,18] has been demonstrated. In [5], by using a coupling stub as the capacitive feed, two wide operating bands are achieved to cover GSM850/900/1800/1900 quad-band operation for the loop antenna with an occupied volume of 3.4 cm 3 .In the proposed design, the loop antenna is formed by mounting a meandered loop strip onto the surfaces of a foam base of 60 ϫ 10 ϫ 3 mm 3 (1.8 cm 3 ) only. The antenna is then surface-mounted ...

Section: Seven-band Surface-mount Loop Antenna With a Capacitively Comentioning

confidence: 99%

Seven‐band surface‐mount loop antenna with a capacitively coupled feed for mobile phone application

Wong

2008

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“…The proposed PIFA comprises two separate radiating strips of different lengths supporting two quarter-wavelength resonant modes at about 900 and 1900 MHz. Owing to the use of the coupling feed [12] in the proposed PIFA, the large input inductance seen for the conventional PIFA of using a direct contact feed at around 900 MHz is greatly compensated, resulting in a much smaller input reactance level for the proposed PIFA. This behavior makes it possible for the excitation of a dual-resonance quarterwavelength mode at about 900 MHz, which forms the antenna's lower band to cover GSM850/900 operation.…”

Section: Introductionmentioning

confidence: 97%

Uniplanar coupled‐fed printed PIFA for WWAN operation in the laptop computer

Wong

Liao

2008

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In this article, a uniplanar printed PIFA (planar inverted‐F antenna) with a coupling feed for application as an internal laptop computer antenna for penta‐band WWAN (wireless wide area network) operation is presented. The proposed PIFA has a compact structure and can be easily printed on one side of a small 0.8‐mm thick FR4 substrate of size 11 × 59 mm2, making it very promising to be embedded inside the casing of the laptop computer, especially for the thin‐profile laptop computer. With the coplanar coupling feed, the large inductive input reactance of the PIFA at around 900 MHz is compensated, and dual‐resonance excitation for the antenna's lower band at about 900 MHz is obtained, which allows it to easily cover GSM850/900 operation. A wide operating band is also achieved for the antenna's upper band at about 1900 MHz, and a bandwidth of larger than 500 MHz is obtained to cover GSM1800/1900/UMTS operation. That is, the proposed PIFA covers all the five operating bands of GSM850/900/1800/1900/UMTS for WWAN operation. Details of the proposed PIFA are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 549–554, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24084

“…The feeding strip not only successfully excites the two coupled strips, it can also work as an effective radiator (an inverted-L monopole in this study) and generate a wide 0.25-wavelength resonant mode at about 1600 MHz, which incorporates the two 0.25-wavelength resonant modes at about 900 and 2200 MHz to from a wide operating band of about 1.5 GHz (from about 0.8 to 2.3 GHz) for the proposed PIFA to cover the desired GSM850/900/1800/1900/ UMTS operation. Note that the behavior of the feeding strip working as both an exciter and a radiator in the proposed coupled-fed PIFA is advantageous over the corresponding feeding strip in the internal coupled-fed mobile device antennas which mainly work as an exciter only [22][23][24][25][26]. This advantageous behavior of the feeding strip results in a simple structure for the proposed PIFA, yet it can still generate a wide operating band for the penta-band WWAN operation.…”

mentioning

confidence: 99%

Wideband coupled‐fed PIFA for HAC penta‐band clamshell mobile phone

Chen

2009

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10, the fidelity of the proposed antenna is larger than 0.85 in the whole angle range of , which ensures the similarity between two pulses mentioned earlier. As shown in Figure 11, for the three different observation angles of , the peak-to-peak normalized value is 1.05, 1.5, and 2, respectively. The value decreases to 52.5% (Ϫ5.59 dB) at ϭ 90°, and 75% (Ϫ2.49 dB) at ϭ 45°, compared with the maximum one at ϭ 0°.In general, the results shown in Figures 8 -11 show that the proposed antenna is very useful in TOA measurement of positioning systems with different orientation change of antenna. CONCLUSIONA novel UWB square slot antenna with circular polarization is proposed and studied in this letter. It is investigated both in frequency and time domain. Results show that it has a 10-dB impedance bandwidth from 2.7 to 5.0 GHz, and a 3 dB axial ratio bandwidth from 3.5 to 4.8 GHz. This study shows that the proposed antenna can be used in lower UWB system generating circular polarization and in TOA positioning systems, and has more application value because it can be easily fabricated and integrated with other circuit components. ACKNOWLEDGMENTThis work was supported by the ASTAR SERC under grant 052-121-0086. 6. X.M. Qing, Z.N. Chen, and H.L. Chung, Ultra-wideband circularly polarized wide-slot antenna fed by three-stub hybrid coupler, In: IEEE international conference on ultra-wideband (ICUWB), 2007, pp. 487-490; art. no. 4380994. 7 .19-2007 [1]. To meet the HAC standard, several studies on the near-field EM (electromagnetic) fields radiated from a mobile phone have also been reported [2][3][4][5]. Among the studies, a clamshell mobile phone embedded with a wideband coupled-fed printed loop antenna of size 5.8 ϫ 10 ϫ 45 mm 3 (2.6 cm 3 ) has been shown to cover the GSM850/900/1800/1900/UMTS (824 -894/890 -960/ 1710(824 -894/890 -960/ -1880(824 -894/890 -960/ /1850(824 -894/890 -960/ -1990(824 -894/890 -960/ /1920(824 -894/890 -960/ -2170 penta-band WWAN operation and satisfy the HAC standard over the five operating bands [5]. The good HAC result makes the studied penta-band clamshell mobile phone in [5] a hearing-aid compatible communication device. However, the available promising internal anten- nas suitable for HAC penta-band mobile phone applications are still very few in the published articles. In this article, we present another promising wideband internal antenna suitable for covering the GSM850/900/1800/1900/UMTS bands and satisfying the latest HAC standard ANSI C63.19-2007, effective on June 6, 2008 [1]. The proposed antenna in this study is a coupled-fed PIFA, which is different from the loop-type antenna in [5,6] and shows a small occupied volume of 6 ϫ 5.8 ϫ 45 mm 3 or about 1.6 cm 3 only, much smaller than that (about 2.6 cm 3 ) in [6]. The coupled-fed PIFA has a simple structure and comprises two coupled strips of a longer one and a shorter one, both capacitively fed by a common feeding strip. The proposed PIFA is easy to fabricate at low cost by printing on a thin dielectric substrate and...