A folded and bent internal loop antenna for GSM/DCS/PCS operation of mobile handset applications

Abstract

A novel dual band-notched monopole ultra-wideband antenna is proposed, in which the parasitic strip creates one band-notch at 5.5 GHz and the tuning stub produces another band-notch at 3.5 GHz.The experimental results show that the proposed antenna, with a compact size of 20 ϫ 31.5 mm 2 , has a bandwidth of 3. 1-10.6 GHz with voltage standing wave ratio (VSWR) less than 2, except the bandwidths of 3. INTRODUCTIONWith the development of modern wireless and mobile communication, the ultra-wideband systems have attracted much attention recently because of its great advantages including high speed data rate, small size, and low power consumption. However, according to IEEE 802.11a, HIPERLNA/2, and IEEE 802.16, some narrow bands, such as WLAN systems (5.15-5.825 GHz) and WIMAX systems (3.3-3.7 GHz), exist during the bandwidth of ultra-wideband (3.1-10.6 GHz). Therefore, to avoid EM interferences between these systems and UWB communication systems, a band elimination characteristic is necessary in UWB antennas. Recently, several UWB antennas with frequency band-rejection function have been reported [1][2][3][4][5][6]. But, most of the proposed antennas only have one band-notched characteristics [1][2][3]. Two UWB antennas with dual band stops have recently been proposed [4, 5]. The dual band stops are formed by cutting two or three U-shaped or C- shaped slots into antenna. Because of the allocation, shape, width, and length of the slots have intensive influence to the bandrejection characteristic, it is difficult to fabricate and adjust the central frequencies of the notched bands.In this letter, a simple UWB antenna with a novel dual bandnotched structure is proposed. By using the parasitic strip and the tuning stub, dual band stops will be created. By only changing the lengths of the parasitic strip and the tuning stub, we can alter the central frequencies of the dual notched bands easily and separately. In addition, there is no sensitive variable to control antenna bandnotched characteristic, so it is facile to fabricate. Details of the antenna design are described, and both simulated and measured results are given. Figure 1 illustrates the geometry and configuration of the proposed UWB antenna, which is printed on the FR4 substrate with a thickness of 1 mm and dielectric constant of 4.4. The antenna size is 20 ϫ 31.5 mm 2 , and the feeding structure of 50 ⍀ microstrip line is used. The proposed antenna is composed of a rectangular ground with a parasitic strip [1], a planar rectangular radiation patch with a wide slot, which load a tuning stub [6]. The radiation patch has been beveled, which ensures good impedance match over a broad bandwidth [4]. And the wide slot antenna has the simple structure and supplies the omnidirectional patterns [7]. A parasitic strip is printed on the bottom side of the substrate, which leads band-notched characteristic at 5.5 GHz. The spacing between the ground and the parasitic strip is 1 mm. To obtain another stopband, a tuning stub is inserted to the wide slot [6], whi...

Very‐small‐size printed loop antenna for GSM/DCS/PCS/UMTS operation in the mobile phone

“…In the recent studies [1][2][3][4][5][6][7], the loop antennas have been shown to be promising candidates for application in the mobile phone as internal multiband antennas with reasonable occupied size. These multiband loop antennas are generally achieved by printing the desired loop metal pattern on the system circuit board or thin dielectric substrate [1][2][3], forming the loop metal pattern on the surfaces of the chip base as surface-mount elements [4], or mounting the loop metal strip above the system ground plane of the mobile phone [5][6][7]. For these reported loop antennas, however, they are mainly operated at their 0.5-wavelength resonant mode to form the antenna's lower band to cover GSM (890 -960 MHz) operation.…”

“…The limitation can be overcome by linearization techniques. A number of linearization methods have been reported to reduce nonlinear distortion products of a direct-modulated LD [3][4][5][6]. The optical feed-forward technique provides better linearity and wider bandwidth than the other techniques as shown in Figure 1.…”

“…However, it has disadvantages such as higher cost and complexity of the total system. The reported optical feed-forward transmitter was demonstrated by using hybrid-typed RF and optical components; therefore, the transmitter volume was bulky [5,6]. Generally, the compact optical transmitter has many merits as system construction cost and maintenance in the in-building RoF system.…”

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

“…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].…”

“…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].…”