Chun-Yih Wu

Internal small-size PIFA for LTE/GSM/UMTS operation in the mobile phone

In the near future, it is expected that the LTE (long term evolution) service [1] will become very attractive for the mobile users. With the LTE incorporated to the mobile devices with the existing GSM/UMTS operation, ubiquitous mobile broadband coverage is promising to become a reality. However, it is a big challenge to design an embedded antenna in the limited space of the mobile phone to cover all the LTE/GSM/UMTS bands. In this paper, we present a promising small-size coupled-fed printed PIFA to cover the eight-band LTE/GSM/UMTS operation. The proposed antenna requires a small footprint of about 415 mm2 only, which is comparable to that of the recently reported printed PIFA for the GSM850/900/1800/1900/UMTS penta-band operation [2], [3], yet it is capable of generating two wide operating bands to respectively cover the LTE700/GSM850/900 (698~960 MHz) and GSM1800/1900/UMTS/LTE2300/2500 (1710~2690 MHz) operation. Experimental and simulation results of the constructed prototype are presented.

A novel antenna pattern switching mechanism for WLAN application

A novel pattern-switchable antenna system design with compact size and low complexity is proposed. The proposed system consists of a PIFA and two miniaturized current draggers. Each current dragger, a small radiator without signal-feeding, is controlled by a pin diode to switch the sinking RF current. Four switching states provide the proposed antenna system four radiation patterns for environmental adaptation. Details of the antenna design are shown, and the measured results for the constructed prototype are also exhibited and discussed.

A small-size penta-band WWAN antenna integrated with USB connector for mobile phone applications

An internal WWAN mobile phone antenna formed by a coupled-fed PIFA and a simple printed monopole to integrate with a USB connector is presented. The proposed antenna is suitable to be mounted at the bottom of the mobile phone, and the USB connector integrated therein serve as a data port for the mobile phone. In addition, the antenna requires a small footprint of less than 10 × 60 mm2 on the system circuit board and shows a thin thickness of 3 mm, making it suitable for slim mobile phone applications. The coupled-fed PIFA in the proposed antenna generates a wide lower band for the GSM850/900 operation (824~960 MHz), while the printed monopole contributes a resonant mode at about 1800 MHz to incorporate a higher-order resonant mode of the coupled-fed PIFA at about 2050 MHz to form a wide upper band covering the GSM1800/1900/ UMTS operation (1710~2170 MHz). Penta-band WWAN operation is hence achieved for the proposed antenna. The SAR results for the proposed antenna with the presence of the head and hand phantoms are also studied. The obtained results are presented and discussed.

Multiband 4-port MIMO antenna system for LTE700/2300/2500 operation in the laptop computer

A multiband 4-port MIMO antenna system for LTE700/2300/2500 operation in the laptop computer is presented. It mainly consists of a pair of two-antenna structures symmetrically disposed at right and left upper corners of the supporting metal frame of the laptop display respectively. The proposed two-antenna structure comprises two the same compact antenna designs covering LTE700/2300/2500 bands and orthogonally locating at two adjacent edges of the upper right or left corner. By simply designing a grounded short strip resonator embedded in-between the two nearby compact antenna designs as a higher-band wavetrap and an un-grounded long folded line resonator as a mutual coupling cancellation mechanism for the lower operating band of them, good isolation and low correlation coefficient are obtained between antenna ports of the two-antenna structures over the whole LTE700/2300/2500 bands to achieve a 4-port MIMO antenna system successfully.

Internal LTE/WWAN handset antenna integrated with solar cells for performance improvement

An internal LTE/WWAN handset antenna integrated with solar cells for performance improvement is presented. By simply designing an inverted-L current guiding structure to be coupled with series solar cells on the casing, the lower operating bandwidth and radiation efficiency of an internal handset antenna with a small-size connected system ground can be greatly enhanced to easily achieve multi-band operations. With this approach, the functionality of solar cells and internal antenna performance can both be increased. The constructed proposed antenna shows that two wide operating bandwidth can be generated to easily cover the LTE/WWAN 8-band operations successfully.

High gain dual-band antenna using photovoltaic panel as metamaterial superstrate

A novel planar dual-band antenna by using a panel of photovoltaic cells as a metamaterial layer for dual-band operation is presented. A 10-Watt, 72-cell unmodified commercial photovoltaic panel is applied as a transparent layer in the first operation band and as a semi-transparent layer for λ/2 Fabry-Pérot cavity in the second operation band to achieve high antenna gain. Unit-cell transmission analysis is adopted to determine the frequency point of operation. The proposed prototype achieves remarkable 17.3 dBi and 6.6 dBi antenna gain at 3.5 GHz and 1.23 GHz, respectively fed by a dual-band dipole. With the aid of PV panel, the antenna can support an upper band at about 3550 MHz to cover the WiMAX 3.5 GHz (3400–3600 MHz) operation band and a lower band at about 1185 MHz to cover the 70 MHz operation bandwidth. The very combination of photovoltaic cell and antenna exhibits high fill factor, high-gain, and simple construction characteristics.

Compact unibody dielectric rod antenna for mm-wave communication

In this paper, we present a compact, low cost, high performance antenna design for mm-wave communication. A unibody dielectric rod antenna with bent waveguide tube section is injection molded from common plastic material. The compact antenna, which is connected to a wideband transition on a planar multilayer board, is easily fitted into small devices. Instinctively adjustable gain and beam direction cooperated with good radiation performance are promising for various kinds of devices with diverse operation scenarios.

Compact beam-switching antenna with shaped ground for MIMO application

A novel commercial-able 3-sector antenna architecture with 6 digitally selectable basic switchable radiation patterns is proposed. Each sector is composed of a driven PIFA, a trimming slit and a RF current dragger. Each current dragger, a small resonator directed connect to system ground, could be controlled by General Purpose Input/Output (GPIO) signal to switch the sinking RF current. Details of the antenna design are shown, and the measured results for the constructed prototype are also exhibited and discussed.

Novel SAR-reducing add-on cover for MIMO handheld device

In this paper, we present an innovative wave-guiding structure for reducing EM power absorbed by human body. A MIMO handheld device with the proposed wave-guiding structure, constructed of metal patch or photovoltaic panel, can effectively reduce its SAR value. The radiation efficiency and frequency response are affected slightly when the proposed structure is presented. Thus the wave-guiding structure with thin profile can be easily integrated with mobile phone or as an add-on protecting case without modifying the existing antennas. Two types of wave-guiding structures for 2.6 GHz WiMAX MIMO handheld device are constructed and measured. The simulated and the measured results confirm the effectiveness of our proposed SAR-reducing structure.

A novel antenna beam switching technique on mobile devices for MIMO applications

In this article we will introduce an antenna structure with reconfigurable pattern, which comprising an active antenna and current draggers. We treat the antenna ground as a part of the radiator. Therefore, controlling the Rf current on antenna ground can manipulate the radiation pattern of the antenna. The current dragger, which intrinsically is a kind of pseudo antenna or a low-Q resonator, is installed on the antenna ground. With a controller and switches, we can change the rf current distribution by enabling or disabling the current draggers. It was confirmed that by changing the control current to the switches, the main beam direction of the antenna can be switched in the azimuthal plane. The antenna was fabricated and measured and the results for the return losses show reasonable agreement.