Zhengwei Du

A Novel Dual-Band Printed Diversity Antenna for Mobile Terminals

A novel dual-band printed diversity antenna is proposed and studied. The antenna, which consists of two back-to- back monopoles with symmetric configuration, is printed on a printed circuit board. The effects of some important parameters of the proposed antenna are deeply studied and the design methodology is given. A prototype of the proposed antenna operating at UMTS (1920-2170 MHz) and 2.4-GHz WLAN (2400-2484 MHz) bands is provided to demonstrate the usability of the methodology in dual-band diversity antenna for mobile terminals. In the above two bands, the isolations of the prototype are larger than 13 dB and 16 dB, respectively. The measured radiation patterns of the two monopoles in general cover complementary space regions. The diversity performance is also evaluated by calculating the envelope correlation coefficient, the mean effective gains of the antenna elements and the diversity gain. It is proved that the proposed antenna can provide spatial and pattern diversity to combat multipath fading.

Reducing Mutual Coupling of MIMO Antennas With Parasitic Elements for Mobile Terminals

Mutual coupling is a critical problem in the design of MIMO antennas because it deteriorates the performance of MIMO systems, which not only affects the antenna efficiency but also influences the correlation. Therefore, in this paper, using parasitic elements to reduce mutual coupling is studied. By adding parasitic elements a double-coupling path is introduced and it can create a reverse coupling to reduce mutual coupling. As an example, a dual-slot-element antenna with parasitic monopoles for mobile terminals is described. The discussion on channel capacity shows that the antenna can be considered as a good candidate for MIMO systems. Furthermore, based on the study of current distributions, it is concluded that the technique is sensitive to relative positions between parasitic elements, and relative positions between active element and parasitic element. Finally, we also extend the technique to a tri-element antenna.

A planar monopole antenna design with band-notched characteristic

This paper proposes a novel type of ultrawide-band (UWB) antenna, which has a low voltage standing wave ratio (VSWR) while excepting from interference with existing wireless system with band notched characteristics. The bandwidth and central frequency of the notched band can be adjusted with ease by proper selection of antenna parameters. Simulation results well justify the design methods presented in the paper. As an important example, a band-notched antenna that yields an impedance bandwidth of 3.1-10.6 GHz with VSWR<2, except the bandwidth of 5.15-5.825 GHz for IEEE802.11, is proposed and evaluated.

Compact planar monopole antenna for multi-band mobile phones

A novel planar monopole antenna suitable for mobile handset applications is presented in this paper. The antenna is mainly composed of a rectangular radiating patch with a meandered slot on, and due to the slot three branches are constructed, two resonating branches and a tuning one. The antenna is printed on an FR4 substrate and fed by a 50/spl Omega/ microstrip line. A prototype has been fabricated and studied. The resulting antenna is able to operate in the GSM, DCS, PCS, UMTS and WLAN bands with a voltage standing wave ratio (VSWR) better than 2.5. Both simulated and measured results are presented.

A novel compact wide-band planar antenna for mobile handsets

A novel printed compact wide-band planar antenna for mobile handsets is proposed and analyzed in this paper. The radiating patch of the proposed antenna is designed jointly with the shape of the ground plane. A prototype of the proposed antenna with 30 mm in height and 50 mm in width has been fabricated and tested. Its operating bandwidth with voltage standing wave ratio (VSWR) lower than 3:1 is 870-2450 MHz, which covers the global system for mobile communication (GSM, 890-960 MHz), the global positioning system (GPS, 1575.42 MHz), digital communication system (DCS, 1710-1880 MHz), personal communication system (PCS, 1850-1990 MHz), universal mobile telecommunication system (UMTS, 1920-2170 MHz), and wireless local area network (WLAN, 2400-2484 MHz) bands. Therefore, it could be applicable for the existing and future mobile communication systems. Design details and experimental results are also presented and discussed.

A Compact Multiband Planar Antenna for Mobile Handsets

A novel compact planar antenna is presented in this letter, which can operate in five bands: GSM (890-960 MHz), DCS (1710-1880 MHz), PCS (1850-1990 MHz), UMTS (1920-2170 MHz), and WLAN (2400-2484 MHz). Consisting of three resonant branches and one tuning branch, the antenna occupies an area of 38.5 times 15 mm2. Due to its two-dimensional (2-D) structure, the antenna is directly printed on the circuit board with low cost, and can be easily integrated with other parts of the circuits of mobile handsets. A prototype has been fabricated and tested, and the experimental results validate the design procedure

A compact planar inverted-F antenna with a PBG-type ground plane for mobile communications

The ground plane affects the characteristics of a planar inverted-F antenna (PIFA) significantly. Using the idea of the high-impedance surface to construct the ground plane, a new type of compact PIFA with a photonic bandgap type (PBG-type) ground plane is proposed. Both the traditional PIFA and the proposed antenna are analyzed using the finite-difference time-domain (FDTD) method in detail. It is found that the two antennas have similar directivity pattern characteristics, but the size of the latter can be reduced obviously. The results also show that the bandwidth of a traditional PIFA is not greatly affected by the thickness of the metallic ground plane and that the shapes of the directivity patterns are not greatly affected by the ground plane under the small size condition. The operating-frequency band of the proposed antenna can be adjusted by changing the dielectric substrate thickness of the ground plane. They are suitable for mobile communication applications.

A Wideband Printed Dual-Antenna System With a Novel Neutralization Line for Mobile Terminals

A wideband printed dual-antenna system for mobile terminals is presented. The dual-antenna, consisted of two symmetric antenna elements and a neutralization line (NL), is printed on a printed circuit board. The antenna element is an F-like monopole with a grounded branch. The working mechanism of the dual-antenna is analyzed based on the S-parameters and the surface current distributions. A prototype shows the measured -10-dB impedance bandwidth is 1.09 GHz (1.67-2.76 GHz) and the measured mutual coupling is lower than -15 dB at the 1.7-2.76-GHz bands. It covers the GSM1800, GSM1900, UMTS, LTE2300, LTE2500, and 2.4-GHz WLAN bands. The radiation patterns are measured, and the diversity performance is evaluated .

A Wideband Printed Dual-Antenna With Three Neutralization Lines for Mobile Terminals

A wideband printed dual-antenna for mobile terminals is studied. The dual-antenna, consisting of two symmetric antenna elements and three neutralization lines (NLs), is printed on a printed circuit board. The three NLs reduce the mutual coupling within a wide frequency band. The working mechanism of the three NLs is analyzed based on the S-parameters, the surface current distributions, and a simplified equivalent model which provides intuitive instructions to optimize the three NLs. A prototype shows that the measured -10 dB impedance bandwidth is 1.3 GHz (1.62-2.92 GHz) and the measured mutual coupling is lower than -15 dB at the 1.66-2.84 GHz band. It covers the GSM1800, GSM1900, UMTS, LTE2300, LTE2500, and 2.4-GHz WLAN bands. The radiation patterns are measured and the diversity performances are evaluated.

A Novel Pattern Reconfigurable Antenna Array for Diversity Systems

In this letter, a novel pattern reconfigurable antenna array for mobile terminals is presented. The proposed antenna array consists of two symmetrically reconfigurable monopoles, which are located symmetrically at the upper-right and upper-left corners of a printed circuit board (PCB). In each monopole, two PIN diodes are used to change the radiation structure and the ground current distribution, which results in different radiation patterns. The reconfigurable antenna array has 2 times 2 operating modes, and the measured results are provided. According to the measured results, the correlation coefficients and the diversity gains are calculated. The proposed antenna array has potential applications in diversity system for mobile terminals.