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From the viewpoint of diversity, this paper presents the applications of element-level pattern diversity (ELPD) technique in the synthesis of array antennas. The application examples include the linear array antennas, the concentric loop array antenna, conformal array antenna and the time-modulated array antenna. With one more degree of freedom in the synthesis, this technique exhibits many advantages...
Miniaturized frequency selective surfaces (FSSs) have been intensively investigated because of the space limitation in practical applications, such as wireless communication system working at low frequencies. Loading lumped capacitor is an effective miniaturization method to achieve the unit cell size as compact as λ0/15 (λ0 refers to the resonant wavelength in free space) [1, 2]. But this approach...
This paper proposes three schemes for three scenarios to realize 4-D beampatterns. The synthesis of the unconventional arrays is based on the time-modulated optimized frequency offset. The retrodirectivity and harmonics are also used for multi-targets. Simulated results validate the proposed ideas.
An antenna optimization method is presented which is based on the spectrum Green's functions and the artificial bee colony (ABC) optimization algorithm to obtain the required radiation patterns. The method is simple and very efficient since it is mainly dependent on analytical formulas. To exhibit the flexibility and validity of the method, a dual-band resonator antenna with two required operating...
In this paper, we propose a new concept of frequency diverse phase-conjugating retrodirective array (FD-PCA) with range-focusing capability for multi-targets. In the conventional PCA, the phase-conjugating mixers in each channel are fed from a common LO signal at twice the RF frequency. In the proposed FD-PCA, an additional small frequency offset across the phase-conjugating mixers is added. Due to...
A novel motion compensation method for single RF channel digital beamforming array is proposed. The method is based on the conception of time reversal. It outperforms the existing method as it does not require the prior information about the number of targets and the Doppler frequencies. Simulation result demonstrates the effectiveness of the proposed motion compensation method. Additionally, the...
In this paper, a high gain conical beam antenna with large beam-pointing angle has been investigated. Total prototype contains a three section circular waveguide aperture antenna which operates in TM03 mode in order to generate a primary conical beam and a new hemitorus lens-reflector as the secondary large aperture radiator. Through optimized design, the gain of 12 dB and a beam-pointing angle of...
A circular periodic dielectric rod antenna operating at 37.5 GHz is proposed. By choosing different periodic structures, radiation patterns of dual conical beams are obtained. The simulated impedance bandwidth of the antenna is 9.6% at center frequency of 37.5 GHz. The maximum beam pointing angles at 37.5 GHz are 117.5° and 123.2° with related gains 11.3 dBi and 11.18 dBi, respectively. The frequency...
A dual-band dual-polarized patch antenna is proposed for WiMax and WLAN systems. Impedance bandwidths of 7.5% and 9.6% can be achieved at 3.6 GHz and 5.2 GHz, respectively. The asymmetrical U-slot has been used to generate the orthogonal modes for circular polarization at 3.6 GHz with a 3dB axial ratio bandwidth of 0.7%, and the linear polarization is obtained by cutting a symmetrical U-slot on the...
A novel frequency selective surface (FSS) with miniaturized element is presented, in which each periodic cell consists of a convoluted ring slot. The 2.45 GHz FSS with such structure is designed, the simulated results show that the FSS dimension is miniaturized to 0.158 λ (λ refers to the resonant wavelength of 2.45GHz). In addition, it also has good stability to oblique incidence waves for both TE...
A dual-polarized Fabry-Perot (FP) resonator antenna with high gain is presented. Two orthogonal polarized rectangular patches fed by coaxial probes are performed as primary radiators. A frequency selective surface (FSS) of square patch array is used as the partially reflecting surface (PRS) cover to enormously increase the directivity. Bandwidths of 3.5% and 4.7% have been realized for two ports,...
This paper presents a low loss slow-wave meander-line unit for frequency scanning antennas based on the even-mode bilateral broadside-coupled suspended microstrip line (BSML). By symmetrically printing metal strips on both sides of the substrate and by biasing an equi-voltage to both of them, the even mode of BSML is excited and this transmission line exhibits very low loss. The losses in straight...
A calibration method is proposed for the single RF channel digital beamforming (DBF) Antenna Array. The on-line test of the 0/π phase shifters is carried out by using time sequence phase weighting (TSPW) technique based on the known incident plane wave. After errors of all the shifters being obtained, the complex distribution on the aperture could be corrected. The corrected data are then used to...
In this paper, a conical beam antenna with wide elevation angle coverage has been proposed. Two stacked circular patch antennas with different elevation angles have been designed operating at TM01 and TM03 mode respectively. A single pole double throw (SPDT) switch is used to switch the conical beams produced from two antennas. The conical beam angle coverage is extended without the loss of gain....
The method based on the discrete approximate image theory to calculate Green's function for thin truncated grounded dielectric substrate has been proposed. Through assuming the truncated edges as perfectly magnetic conductors (PMC), the solution has been obtained by using the images caused from the multi-reflections of the magnetic walls. The simulated results demonstrate not only the validity of...
A Fabry-Perot (F-P) antenna with conical beam is presented. Cavity structure with a cross-slot FSS superstrate is designed resonant at a prescribed flare angle and a specified defect frequency by combining leaky wave and EBG antenna theory. By using a circular patch as the primary source, the aperture distribution can be controlled with appropriate mode to achieve desirable gain and side lobe level...
This paper presents the DCI-PEEC method in the application of electromagnetic simulation. The exact full-wave Green's function for multi-layered media from discrete complex image (DCI) makes partial element equivalent circuit (PEEC) method available for the ultra-wideband modeling. An example of S parameter calculation for on-chip spiral inductor verifies this method.
A microstrip Wilkinson power divider with harmonic suppression and size reduction is presented in this paper. The proposed power divider has reduced its occupied area to 37.6% of the conventional design. Furthermore higher order harmonics are effectively suppressed. The whole design is validated by the full-wave electromagnetic simulation results.
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