Wideband Compact Antennas for Wireless Communication Applications

Recent technologies enable wireless communication devices to become physically smaller in size. Antenna size is obviously a major factor that limits miniaturization. In the past few years, new designs of low-profile antennas for handheld wireless devices have been developed. The major drawback of many low-profile antenna designs is their narrow impedance bandwidth. Furthermore, the market trend of personal wireless devices is moving toward a universal system that can be used anywhere and rapid expansion of the wireless communication industry has created a need for connectivity among various wireless devices using short-range wireless links in the Bluetooth operating band to get rid of the cable connections. This requires therefore multiple frequency band operation. In summary, physically small size, wide bandwidth, and high efficiency are the desired characteristics of antennas in mobile systems. This dissertation presents a comprehensive analysis of a new wide-bandwidth compact antenna, called WC J-pole antenna, covering 50 % impedance fractional bandwidth. A set of guidelines is also provided for a bandwidth-optimized design at any frequency. A few design variations of the proposed antenna are also presented for existing commercial wireless applications. Efficiency is perhaps the most important characteristic of small antennas for mobile systems. An extension of the Wheeler cap method to moderate-length and wideband antennas is developed to measure quickly efficiency. The dissertation also provides a review of human operator interaction with handset antennas. Since the proposed antenna is intended to be used in the proximity of human body and in a casing, coupling effects of human body and casing on the antenna characteristics and radio frequency (RF) energy absorption into the human body are investigated.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Electrical and Computer Engineering

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2004

Author dc:creator

• Huynh, Minh-Chau

Chair dc:contributor.committeechair

• Stutzman, Warren L.

Committee members dc:contributor.committeemember

• Schmittmann, Beate
• Pratt, Timothy J.
• Safaai-Jazi, Ahmad
• Davis, William A.

• radiation efficiency
• radiation effects
• Small antenna
• compact antenna
• wideband antenna

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-12012004-175318

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/29853