A novel method for a beam pattern reconfigurable circularly polarized (CP) transmitarray antenna based on passive metasurface is proposed by a rearrangement of source antennas. Two source antennas among eight source antennas are selected for the fine beam steering. The beam steering angle can be finely controlled by the positions and phase difference of the source. Moreover, this kind of transmitarray antenna can be utilized to generate multibeam by the combination of the source antennas for radiation to different directions. To verify its feasibility, the planar CP source antenna is designed to operate at 5.8 GHz. Also, the metasurface consists of four layer separated by four substrates to cover full transmission phase variation of 2π, and the metallic layers are designed to circular patches. As a result, the steering angle is experimentally observed at each 0, +20, and +40°, and dual beam radiating to −30 and +30° also is measured.

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The spurious radiation of patch antennas is suppressed by the band‐stop characteristic of split‐ring resonators (SRRs). The SRRs are located near the feed line of the upper substrate so as to couple the perpendicular magnetic field to the SRRs. The SRRs can be characterized with negative permeability and positive permittivity around the resonance frequency and, thus, waves cannot propagate. To eliminate the first and second spurious radiations, the design equations of a band‐stop filter using SRRs are suggested. The reflection coefficient and the far‐field radiation pattern of a patch antenna with SRRs are obtained via full‐wave simulation and measurement. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 283–287, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21328

A compact partial H-plane filter consisting of quarter wavelength resonators is proposed. The previously proposed partial H-plane filter [1] has the same pass-band responses as those of conventional E-plane filter, while its cross section is one quarter. The proposed filter in this paper is designed by utilizing quarter wavelength resonator, so its total length is further reduced and its spurious responses are improved. The filter is fabricated with coax to partial H-plane waveguide transition in H-band. Measured results are in good agreement with computed results.

A dual band omnidirectional circularly polarized (CP) antenna is presented based upon new concept of combining two orthogonal modes of epsilon‐zero resonance (EZR) and mu‐zero resonance (MZR) in this article. The antenna has the CP characteristic by two circularly ring‐structured double negative (DNG) transmission lines. One DNG transmission line has higher frequencies of EZR and lower frequency of MZR while the other DNG transmission line has higher frequencies of MZR and lower frequency of EZR. The EZR and MZR modes at the same frequency have a vertical and a horizontal polarization with 90° phase difference, respectively. In the EZR mode, a vertical polarization is generated like an electric monopole so that the EZR antenna radiates omnidirectionally. The MZR antenna makes a horizontal polarization by the circular ring current like a magnetic dipole loop which also radiates omnidirectionally. The analysis and design of the antenna are performed according to theory and simulation based on a dispersion diagram and E‐field distribution. Finally, the reasonable performances of the antenna such as a reflection coefficient, a CP gain, an axial ratio, and a far‐field radiation pattern are obtained in dual band.