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A printed collinear antenna with a narrow (10 mm) width showing high-gain omnidirectional radiation is presented. The antenna comprises three half-wavelength elements of one strip dipole, one meandered line, and one straight strip connected in series, and has a total height of only 113.5 mm (about 92% wavelength of the frequency at 2442 MHz) for operation in the 2.4-GHz WLAN band. Due to the meandered line, in which the excited surface current has a phase opposite to that of the strip dipole and straight strip, the destructive radiation in the azimuthal plane for the antenna is suppressed. Conversely, the strip dipole and straight strip are constructive with regard to radiation, which leads to high-gain omnidirectional radiation for the antenna. A prototype showing good omnidirectional radiation (with gain variations less than 1.5 dB in the azimuthal plane) with a high gain level of about 4.4 dBi across the 2.4-GHz WLAN band is presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 348–351, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20631

A small-size circularly polarized ceramic-chip antenna suitable for surface mounting on a system circuit board is presented. The antenna mainly comprises a square radiating patch with a cross slot on the top surface, a square ground plane on the bottom surface, and a side-feed conformal strip on the side surface. For obtaining circular polarization (CP) radiation for global positioning system (GPS) operation at 1575 MHz, a prototype is constructed using a square-disk ceramic chip of dimensions 12 × 12 × 4 mm3 and having relative permittivity of 90, and the experimental results are presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 300–302, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11360

A novel surface-mountable dual side-feed circularly polarized ceramic chip antenna on a system circuit board is presented. The antenna mainly comprises a square radiating patch, a square ground plane, and two vertical conformal strips for the dual side-feed, which are printed on the top, bottom and side surfaces of a ceramic chip. For obtaining circular polarization (CP) radiation for global positioning system (GPS) operation at 1575 MHz, a prototype using a square-disk ceramic chip of dimensions 4/spl times/17.5/spl times/17.5 mm/sup 3/ and relative permittivity 45 was studied, and the experimental results are presented.