A single square patch antenna for pattern diversity is investigated. The proposed antenna consists of a double-feed square patch antenna with a rat-race network. By switching the feeding ports, the different radiation patterns for two modes (TM 10 mode and the capacitive-loaded monopole radiating mode) operating over an overlapped frequency band from 1.88 to 2.34 GHz are achieved. TM 10 mode reveals good broadside radiation patterns and the capacitive-loaded monopole radiating mode shows conical radiation patterns. The antenna is fabricated and tested. The measured gains across the common frequency band are 8.9-9.9 dBi and 2.8-3.8 dBi for TM 10 mode and the capacitive-loaded monopole radiating mode, respectively. Besides, the measured bandwidths of -10 dB reflection coefficient are 750 MHz (1.59-2.34 GHz, 38.2%) for TM 10 mode and 880 MHz (1.88-2.76 GHz, 37.9%) for the capacitive-loaded monopole radiating mode. High isolation (<-20dB) between the two feeding ports for the common impedance matching band is achieved. These results make the single dual-port patch antenna an attractive solution for 3G/4G pattern diversity applications such as in gym scenarios.
A synthesis method for orthogonal beam-forming networks (BFNs) with arbitrary N inputs and N outputs is presented. Compared to those formerly developed, the new method allows the design of a BFN in order to not only generate arbitrary N orthogonal beams and N inputs but also to make the 180 • hybrids less. This skill is obtained by means of a new approach to decompose the matrices Q 1 and Q 2 which are mentioned by Sodin. The solution of such a design problem can be carried out by applying QR decomposition based on Givens transformations. Such a design method also takes into account the computer programming realization. Numerical results are obtained through the commercial simulator to prove the correctness of the method. The ease, accuracy, and efficiency of this synthesis method for the design of BFN make it very useful in modern applications of multi-beam antenna arrays. INDEX TERMS Orthogonal beam-forming network, butler matrix, arbitrary N beams, QR decomposition, Givens transformations.
Abstract-A single-layer wideband printed antenna for dual-polarized applications is proposed in this paper. Two orthogonal linear polarizations are achieved by adopting a hybrid feeding technique. The horizontal polarization is excited by an aperture-coupled microstrip feed line while the coplanar waveguide (CPW) feed line is responsible for the vertical polarization. Measurements demonstrate a fairly wide common impedance bandwidth of 56.3% (1.61-2.87 GHz) with SWR ≤ 2 could be achieved. By loading a rectangular patch in the narrow rectangular slot, the isolation between two ports can be improved to better than 40 dB over the entire bandwidth. Moreover, the average gains of the proposed antenna are about 5.8 dBi and 5 dBi for port 1 and port 2, respectively.
A compact Rotman lens is presented in this paper. The compact Rotman lens consists of a lens body and truncated ports with the energy distribution slots. By truncating the long triangular transitions of the traditional Rotman lens, the lengths of lens ports are reduced effectively. However, the impedance discontinuity problem is caused by truncating the triangular transition. To solve this problem, the energy distribution slots are designed between the feed lines and the truncated lens body apertures. The energy distribution slot is evolved from the 1-2 power divider, which creates a transition process for the wave energy propagating from the feed lines and realizes good impedance match between the lens body and the feed lines. To validate the proposed design, a 4×7 Rotman lens has been designed and prototyped at 10 GHz. The Rotman lens exhibits a scanning range of ±33 • , 27% bandwidth for VSWR < 2, and the isolation between beam ports better than 17.2 dB within the operation bandwidth. Basing on the advantages of compact size, low cost, easy processing, and wide bandwidth, the proposed compact Rotman lens may have wide applications in the multi-beam antenna systems.
Abstract-A novel dual-band annular ring slot antenna is investigated. The antenna consists of a center-fed circular microstrip patch antenna with a coupled annular ring. And it is shorted concentrically with a set of conductive vias. By adjusting the parameters of the antenna, the dual resonant frequencies for two modes (TM 01 and TM 02 modes) are achieved. The antenna is fabricated and tested. Results show that the proposed antenna with height of 0.0217λ 0 can provide gains of 3.01 dBi at 2.6 GHz (the receiving frequency) and 5.74 dBi at 2.95 GHz (the transmitting frequency). Good agreement between the measurement and simulation for the return loss and radiation patterns is achieved. The proposed antenna has dual-band characteristics, simple structure, low profile, and omni-directional azimuth radiation pattern. It is suitable for aircraft both receiving and transmitting signals and frequency division duplex (FDD) applications.
A feed network based on substrate integrated waveguide for 38 GHz application is proposed in this article. The network consists of a 90 hybrid, a 180 hybrid, a power divider, and a switchable phase shifter. There are two input ports in the reconfigurable multibeam feed network (RMBFN) and a set of symmetrical radiation pattern will be excited by the two input ports. In addition, the other symmetrical patterns will be obtained by adjusting the different states of the switchable phase shifter. The simulated results show that the S 11 and S 22 are found to be better than −13 dB over 37-40 GHz. Meanwhile, the amplitude of the three output ports is about −6.6 AE 1 dB, and the phase difference is AE60 AE 10 or AE120 AE 10 . When the proposed RMBFN feeds for an antenna array, four different beams with the main beam pointing to the AE22 AE 3 and AE43 AE 3 are obtained.four different beams, reconfigurable multibeam feed network, switchable phase shifter
Abstract-A low-profile antenna is proposed in this letter for realizing dual polarizations with omnidirectional radiation patterns. Vertical polarization is obtained by a modified annular ring slot antenna, and horizontal polarization is obtained by a modified printed arc dipole array. By combining the ground plane of the ring slot antenna and the dipole array on the same layer, the profile of the antenna is reduced to minimum extent. The proposed prototype has a low profile of 0.024λ (λ is the freespace wavelength at 2.4 GHz). To verify the design, the proposed antenna is fabricated and measured. Measured reflection coefficients, isolation, and radiation patterns data agree well with the simulated results. The common band of vertical and horizontal polarizations makes the proposed antenna satisfy the WLAN diversity systems with omnidirectional characteristic.
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