Chih-Ming Su

Dual-band flat-plate antenna with a shorted parasitic element for laptop applications

A novel dual-band flat-plate antenna with a shorted parasitic element for an internal laptop antenna for WLAN operation is presented. The proposed antenna is suitable to be integrated with the supporting metal frame for the display of the laptop and shows a low profile of 5 mm above the metal frame, thus making it easily embedded within the casing of the laptop as an internal antenna. Moreover, the proposed antenna can provide two separate impedance bandwidths of 190 MHz (about 8% centered at 2.4 GHz) and 2140 MHz (about 39% centered at 5.5 GHz), making it easily cover the required bandwidths for WLAN operation in the 2.4 GHz band (about 3.4% bandwidth required) and 5.2/5.8 GHz bands (about 13% bandwidth required). The proposed antenna is studied in detail in this study, and experimental and simulation results are presented.

EMC internal patch antenna for UMTS operation in a mobile device

A novel patch antenna suitable to be applied in a mobile device as an internal antenna having an electromagnetic compatibility (EMC) property with nearby conducting elements is presented. The antenna is easily fabricated from a single metal plate and mainly comprises a top patch and an inverted-L vertical ground wall. Due to the presence of the inverted-L ground wall, which is perpendicular to the system ground plane of the mobile device, the possible fringing EM fields in the surrounding region of the antenna are suppressed. In this case possible coupling between the antenna and the nearby conducting elements is expected to be small, and thus degrading effects on the performance of the antenna are eliminated. A design example of the proposed antenna for Universal Mobile Telecommunication System (UMTS) 1920-2170 MHz operation in a mobile device is demonstrated and discussed.

User's hand effects on EMC internal GSM/DCS mobile phone antenna

The users hand effects on the EMC GSM/DCS antenna embedded in the mobile phone have been presented. Although the EMC antenna is easy to be integrated into a mobile phone with nearby electronic components or conducting elements, the performance of the antenna is still greatly affected when a users hand holds the mobile phone. Even when the phone was hand-held at the bottom, large efficiency drops have been observed, especially for the GSM operation

Embedded DTV antenna for laptop application

A novel embedded DTV antenna for application in laptops has been proposed and studied. The proposed antenna can provide a wide operating bandwidth for DTV signal reception in the UHF band. In addition, the proposed antenna has a narrow width of 10 mm only, thereby making it very promising to be embedded within the spacing between the display and the casing of the laptop to operate as an embedded antenna. The proposed antenna also shows good radiation characteristics for frequencies across the operating band.

Metal-plate shorted T-shaped monopole for internal laptop antenna for 2.4/5 GHz WLAN operation

A T-shaped monopole antenna is a planar top-loaded monopole antenna and has the attractive feature of a low profile. We propose a novel dual-frequency metal-plate shorted T-shaped monopole antenna suitable for WLAN operation in the 2.4 GHz (2400-2484 MHz) and 5 GHz (5150-5350 and 5725-5875 MHz) bands. A prototype with a low profile of 4 mm only has been constructed. It is suitable for embedding within the narrow space between the top edge of the display and the housing of a laptop computer to operate as an internal antenna. Details of the proposed antenna and the experimental results are presented.

Optimized isolation between internal antennas for a dual-network wireless device

Experimental and simulation studies for achieving optimized isolation between two internal UMTS and WLAN antennas for a dual-network wireless device are presented. Results indicate that the isolation of the two antennas is strongly affected by their relative position, and that isolation less than -30 dB is possible for the two antennas. It has also been observed that the isolation is strongly related to the excited surface current distributions in the system ground plane of the wireless device.

Planar inverted-F antenna with a hollow shorting cylinder for internal mobile phone antenna

Planar inverted-F antennas (PIFAs) have been very popular as an internal antenna in small handheld wireless communication devices. Recently, in many wireless devices, a digital camera is embedded and is in competition with the PIFA internal antenna for the very limited space on the system circuit board. We propose a novel design of the PIFA with a large hollow shorting cylinder for application in a mobile phone with an embedded digital camera. The hollow shorting cylinder has a large diameter (8 mm in this case), and it is easy to fit the lens of a practical embedded digital camera inside it. In this case the proposed PIFA and the embedded digital camera together occupy a minimum space, and very small or negligible coupling effects of the embedded camera with the PIFA are expected. A design example of the proposed PIFA for application in a UMTS (Universal Mobile Telecommunication System, 1920-2170 MHz) mobile phone is demonstrated. The experimental results obtained are also presented.

Simplified hand model for the study of hand-held device antenna

This paper proposes a one-layer simplified hand model incorporating the use of 3D FDTD simulation software, SPEAG SEMCAD-X (simulation platform for EMC, antenna design, and dosimetry) for achieving efficient simulation for hand-held device antennas. The case of the GSM/DCS internal mobile phone antenna with the proposed hand model is first presented. Effects of the proposed hand model including the users forearm on the impedance and radiation characteristics of the internal antenna are analyzed. A second case of the DTV antenna in the PMP device with proposed hand model is also studied