Ta-Chun Pu

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 self-shielding open slot antenna for WiMAX MIMO application

A self-shielding open slot antenna has been proposed, constructed and tested. From the simulation and measured results, it is found that the performance of the proposed antenna is almost not affected by the surrounding metal components. Thus the proposed antenna can easily be integrated with different commercial products as an internal antenna. Utilizing this property with proper arrangement of antenna position, the isolation between two self-shielding open slot antennas with a separation 0.24 wavelength is better than 24 dB over the operation bandwidth. Therefore the proposed self-shielding open slot antenna can be considered as a good candidate for MIMO applications.

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.

A high-gain directive superstrate antenna for 60-GHz applications

A high-gain aperture coupled antenna with superstrate structure for 60 GHz communication is proposed. Unprinted dielectric slab acts as superstrate is added above the antenna in order to increase the gain performance. Then, the effective radiated area and transmission line model are used to further enhance the gain. The maximum simulated gain of the antenna with superstrate structure can achieve 15.2 dBi at 60 GHz and is more than 13 dBi all over the 60 GHz band (from 57 to 66 GHz). From simulated results, the radiation patterns are found to be broadside all over the frequency band.

A connector integrated mm-wave antenna

In this paper, we present a new concept of using existing electronic connectors, such as micro USB and audio phone jack, as the main structure of mm-wave antennas. The integrated antenna itself exhibits good radiation performance for 60GHz application. The modified connectors perform original connectivity when plugged and radiate mm-wave signal when unplugged or plugged with radiating enhancing structures. The combinations almost consume no extra footprint of the devices circuit board.

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.