A compact dual-band power divider for GSM/DCS applications is proposed in this letter. Novel planar artificial transmission lines are applied to miniaturize the power divider and achieve wideband response. The proposed dual-band power divider is about 37% of conventional one. The design principle, simulated and measured results are all discussed. The measured results show that good performance can be achieved at the operation frequencies.
In this paper, ultra-wideband and miniaturization, technique for the microstrip monopole patch antenna (MMPA) in wireless applications is presented. Ultra-wideband was achieved by using Printed modified ground plane on a dielectric substrate with 50 microstrip feed line. This technique allows the bandwidth of the MMPA to be ultra-wideband with satisfactory radiation properties and reduce the antenna size. The proposed antenna with modified ground plane provides an mpedance bandwidth (S11 < -10 dB) more than 5.5 GHz corresponding to 116% of fundamental resonant frequency with reduction in antenna size by 20% from original size. For further improvement in antenna characteristics, electromagnetic band-gap (EBG) structure is used. The surface wave was suppressed so the antenna bandwidth was increased to be 3--11 GHz corresponding to 170%, and the antenna size was reduced 43% of its original size. Two types of EBG are used. Holes are drilled around the patch, and embedded circular patches of the electromagnetic band-gap structure with suitable dimension are used. Details of the proposed antenna design have been described, and the typical experimental results are presented and discussed. Commercial software high frequency structure simulator (HFSS®) version 11 was used for the antenna design.
In this paper, we present an innovative method of cross-polarisation suppression by forming the antennas in a so called Clover Array (CA). Such structure enables usage of polarisation diversity even for UWB systems. The simplified theoretical model of operation is presented as well as exemplary results of crosspolarisation patterns. The theory was verified for CA of planar Volcano-Smoke antennas. For fabricated array the cross-polarisation in main beam is below -14 dBi in the whole FCC-UWB frequency range (3.1 GHz - 10.6 GHz).
Miter bend mirror has been designed for microwave transmission between two corrugated waveguides of the same size by iterative phase correction method. Geometrical Optics (GO) approximation has been used in our design at a frequency of 110 GHz. The equivalence principle is also adopted to forward-propagate and backward-propagate the beam onto the miter-bend mirror. The designed miter bend mirror shows a coupling coefficient up to 99.619%, much better than that of a flat mirror. The convergence rate shows that the design is very efficient with only a few iterations required.
An all-dielectric composite route is proposed for the construction of a left-handed material at THz frequency. It is shown that the interaction between the crystal lattice vibration of the polaritonic dielectric and the electromagnetic wave could induce a negative permittivity. By combining the electric inclusion of polaritonic dielectric with the magnetic inclusion based on Mie resonance, the dielectric composite exhibits simultaneously negative permittivity and negative permeability, hence a negative refractive index. Additionally, the simulation results of the electromagnetic coupling between the electric and magnetic inclusions indicate that the behavior of the negative refractive index is closely related to the distance between the two inclusions.
A novel circularly polarised (CP), single-fed widebeam microstrip antenna is presented. The antenna consists of a corner-truncated square patch and a three dimensional circular ground structure. Simulated and measured results show that, owing to the ground structure, the 3 dB beamwidth of the CP radiation can reach more than 165o, which is about 85o, greater than that of a corresponding regular microstrip antenna. It is also shown that experimental results were in good agreement with the simulated performance. Details of the proposed 3-D circular ground structure are described, and the effects of various dimensions of the proposed ground structure on the beamwidth enhancement of CP radiation are studied.
In this paper, a new kind of 3D transition and power divider based on half mode substrate integrated circular cavity (HSICC) is proposed. This novel HSICC transition and power divider can be easily integrated into microwave and millimeter-wave multilayer circuits using LTCC technology. What is more, it can reduce nearly half size of normal SICC resonator and has the advantages of high flexibility, low insertion loss and amplitude imbalance. Two different 3D simulation tools are employed to validate the design method of this novel structure.
The passing center swing back grids (PCSBG) technique, in conjunction with the method of characteristics (MOC), was proposed to model electromagnetic problems featured with rotating objects. The drive of this proposal lays mainly on the fact that MOC defines all field components in the center of grid cell. Its practicability was validated by exhibiting the radiated EM fields from a rotating cylinder which carries surface currents with Gaussian profile and flowing in the axial direction. To clearly demonstrate that the cylinder is rotating and radiating EM fields simultaneously, the following arrangements were made. The cylinder may be equally sliced into an even number of segments that are with and without currents alternatively since a rotating circular cylinder yields no relativistic effects. The computational results showed that the radiated electromagnetic fields bear vortex structures as the cause of rotating cylinder, which serves as the evidences that PCSBG works properly.
A two-port antenna with high isolation for digital television system (DTV), global system for mobile communication (GSM), and universal mobile telecommunications system (UMTS) indoor applications is presented. The antenna consits of a disk loaded sleeve monopole antenna and an inverted-L plate antenna, which are combined into one radiation structure. In addition, by using a choke tube and C-shaped slot inserted into the plate, the isolation between the two ports is impoved. A prototype is constructed and tested. The simulated and meseasued results are given.
a small tapered slot antenna with a notched band for wireless applications is proposed in this paper. A modified transition from microstrip to slotline is used to introduce a notched band from 4.90 to 6.34 GHz. Corrugated edges on the ground is also used to improve the radiation patterns at the lower frequency band. Relatively stable radiation patterns and consistent group delay except the notched band have been obtained as proved experimentally.
The optical properties of birefringent Bragg fiber with a fiber core of 2-dimension (2D) elliptical-hole photonic crystal structure has been study. Elliptical air holes are introduced into the fiber core to form a normal 2D photonic crystal structure with a hole pitch (center-to-center distance between the air holes) much smaller than the operation wavelength of the Bragg fiber. The elliptical-hole photonic crystal structure acts as an anisotropic medium with different effective indices for transmission light of different polarization, which inevitably results in high birefringence (up to the order of magnitude of 0.01) of the Bragg fiber. The proposed Bragg fiber possesses different band-gaps for differently polarized mode. Besides the periodic alternating layers of high/low refractive indices, the bandwidth of the band-gap is also dependent on the effective index of the fiber core, which can be controlled by the area of the elliptical air holes.
Focal region fields of a perfect electromagnetic conductor (PEMC) paraboloidal reflector placed in homogenous and reciprocal chiral medium are analyzed under the effect of high chirality parameter. The chiral medium supports both negative phase velocity (NPV) and positive phase velocity (PPV) modes simultaneously under strong electromagnetic coupling. The geometrical optics (GO) fields have singularities at the focal region. Therefore, to avoid these singularities Maslov's method is used for the focal region fields. The results obtained using this method are solved numerically, and line plots for the reflected field of the paraboloidal PEMC reflector are obtained for different values of admittance of the PEMC paraboloidal reflector and chirality parameter of the medium.
This paper obtains the topological 1-soliton solution of the nonlinear Schrodinger's equation in 1+2 dimensions, with power law nonlinearity and time-dependent coefficients. The solitary wave ansatz is used to obtain the solution. It will also be proved that the power law nonlinearity must reduce to Kerr law nonlinearity for the topological solitons to exist.
An exact analytic solution is presented to the problem of scattering of a plane wave from a perfect electromagnetic conducting (PEMC) elliptic cylinder, using the method of separation of variables. The formulation is carried out by expanding the incident as well as the scattered electromagnetic fields in terms of appropriate angular and radial Mathieu functions and a set of expansion coefficients. The incident field expansion coefficients are known, but the scattered field expansion coefficients are unknown. Imposing the boundary conditions at the surface of the elliptic cylinder leads to the determination of the unknown expansion coefficients in closed form. Results are presented as normalized scattering widths for elliptic cylinders of different sizes and PEMC admittances, to show the effects of these on scattering.
In this article, a novel microstrip-line fed monopole dual band-notched antenna with tapered slot for UWB applications is presented. The tapered slot, making the antenna have a scissors-like shape, is taken into account to enhance the wideband characteristics. In addition, the dual notched bands, from 3.3 to 3.7 GHz and from 5.15 to 5.85 GHz, are achieved by inserting slots on the ground plane and adding circle arc stubs on the radiating patch. Details of the antenna design are described, a theoretical and experimental investigation of the antenna is given as well.
In this paper, a compact, wide fractional bandwidth bandpass filter using a new open slot split ring resonator (OSSRR) defected ground structure and compact microstrip resonating cell (CMRC) is presented. OSSRR is the modified and dual version of the open split ring resonator (OSRR). The band pass filter (BPF) is constructed by cascading lowpass and highpass sections designed using CMRCs and OSSRR respectively. The designed BPF has wide fractional bandwidth of 74%, sharp passband to stopband transition and low passband insertion loss of less than 1 dB. The simulated results are well validated by the experimental results.
A novel compact strip-line fed UWB antenna with band-notched characteristic is proposed. By employing a balanced antipodal structure and strip-line feed, the size of this antenna has been reduced to only 23 mm×27.5 mm with the dielectric substrate of relative permittivity 2.65. Meanwhile, a slot is added onto the radiating patch of the mid metalisation layer to realize the band-notched function, by tuning the length of which suitable rejected frequency band can be obtained. According to the measured results, the proposed antenna has a large bandwidth totally satisfying the requirement of UWB applications (3.1~10.6 GHz) with good stable omnidirectional radiation patterns and gains except in the rejected frequency band (4.9~6.2 GHz). Details of this antenna are described, and the experimental results of the constructed prototype are given, too.
Novel configurations of complementary split ring resonator (CSRR) with dual mesh-shaped couplings and defected ground structures (DGS) are introduced to design the high performance of wide pass-band and stop-band band pass filters (BPF). This paper presents a low insertion loss (-0.82 dB), symmetry and sharper transmission zero level (-51.88 dB), using effective DGS and alternative coupling for CSRR. The filter with center frequency at 1.92 GHz, pass-band from 1.21 GHz to 3.05 GHz (BW = 95.8%) and wider stop-band (extended to 4.2f0 below -20 dB rejection level) is designed and fabricated. Simulation and measured results including surface current distributions and frequency responses are presented and discussed.
A new design technique of microstrip patch antenna is presented in this paper. The proposed antenna design consists of inverted patch structure with air-filled dielectric, direct coaxial probe feed technique and the novel slotted shaped patch. The composite effect of integrating these techniques and by introducing the new multi-slotted patch, offer a low profile, high gain, broadband, and compact antenna element. A wide impedance bandwidth of 27.62% at -10 dB return loss is achieved. The maximum achievable gain is 9.41 dBi. The achievable experimental 3-dB beamwidth (HPBW) in the azimuth and elevation are 60.880 and 390 respectively at centre frequency.
A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f2/f1=1.33. In order to achieve the dual-frequency operation, a rectangular patch is loaded with a stub at one of its radiating edges. To improve bandwidth at each band, two parasitic patches are coupled to the driven element.