Mutual coupling between log-periodic antennas

Numerical techniques are used for the analysis of mutual coupling in arrays of log-periodic dipole antennas. The analysis is formulated in terms of impedance and admittance matrices for the dipole and transmission line networks. Approximations are made to allow the solution for moderately sized arrays to be practical with the existing generation of computers. Antenna patterns for the array are expressed in terms of the current incident on each log-periodic antenna. Results are presented for systems of one, two, and three log-periodic antennas.     

Mutual coupling between microstrip antennas

A theoretical study of mutual coupling between microstrip antennas is presented. The cavity method is used, and from the equivalence theorem application the problem is reduced to interaction of two magnetic loops. The mutual impedance is then calculated from the reaction theorem. Theoretical results and measurements are in good agreement.     

Mutual coupling between short-circuited microstrip antennas

A method has been previously developed for the computations of mutual coupling between the usual rectangular printed antennas. In the letter the short-circuited antennas with three magnetic walls and an electric wall (Fig. 2) are investigated. Using the cavity model with hybrid boundary conditions (magnetic wall and electric wall) and the equivalence theorem, the problem is reduced to the interactions of two U-shaped magnetic currents. Theory and experiment are in very good agreement.     

Anomalous mutual coupling between microstrip antennas

An asymptotic expansion of the microstrip Green's function is used to facilitate a study of mutual coupling between two printed antennas, and coupling versus element separation is presented for substrate parameters of practical interest. For certain substrate parameters, it is found that the magnitude of mutual coupling does not decay monotonically with increasing element separation. Instead, the magnitude exhibits a quasi-periodic oscillation which can be attributed to the interference of surface and space waves. The presentation and discussion of this anomalous behavior is the purpose of the paper. The asymptotic representation of the Green's function, which differentiates space wave terms from surface wave terms when source and observation points are largely separated, is used to characterize the behavior of mutual coupling in the principal planes     

Mutual coupling between microstrip patch antennas

A theoretical approach to the mutual coupling phenomenon between microstrip patch antennas of arbitrary geometry and alignment is presented. The theory employs an equivalent magnetic wall model for each single radiator, a series expansion in resonant modes in connection with a reaction concept treatment of antenna interaction. Good agreement of theoretical and experimental data is observed in a wide frequency range for various element spacings.     

Measured mutual coupling between microstrip antennas

Mutual coupling betweenL-band rectangular, nearly square, and circular microstrip antennas has been investigated experimentally by a series of measurements of theS-parameters. The mutual coupling level decreases monotonically with increasing separation between elements with theE-plane coupling down 20 dB and theH-plane coupling down 25 dB for typical adjacent element spacings. For 1/16 in and 1/8 in substrates atL-band the predominant coupling mechanism is via the space wave since the surface wave is shown experimentally to be small.     

H-plane coupling between rectangular microstrip antennas

A new model that theoretically characterises mutual coupling effects between two rectangular microstrip antennas is presented. Numerical S-parameter results exhibiting mutual coupling effects are reported.     

Mutual coupling between circular disc microstrip antennas

The mutual coupling between microstrip antennas is studied by applying the reaction theorem and the cavity model. A semianalytic formula is derived for disc antennas which takes into account the dependence on the relative angular position of the antennas, as well as on the angular feeding point poisition. Theoretical results are in good agreement with measurements.     

Mutual coupling between cylindrical rectangular microstrip antennas

The effect of curvature and separation on the mutual coupling between probe feed rectangular microstrip antennas printed on a cylindrical surface is studied theoretically and experimentally. To incorporate the interactions between patches through the space wave as well as the surface wave, the rigorous spectral domain approach is adopted. The experiment is performed for the purpose of validation of the theoretical results     

A measurement of the coupling between close-packed shieldedcassegrain antennas

Design and performance details are given for a 0.9-m diameter shielded cassegrain antenna, which will be used in a 13-element close-packed array, The array is designed to make images of brightness fluctuations in the cosmic microwave background radiation. Coupling between a pair of the shielded cassegrain antennas with a separation of 1 m is in the range -110 to -130 dB over the 26- to 36-GHz band     

Mutual coupling between identical planar inverted-F antennas

Mutual coupling between two identical planar inverted-F antennas (PIFA) located on an infinite ground plane is studied numerically. Several arrangements of side-by-side, collinear, parallel-in-echelon, and orthogonal PIFA antennas with element spacing varying from $0.06\lambda$ to $1.20\lambda$ are investigated at the design frequency of 1.9 GHz, and in the $-6\mathrm{dB}$ bandwidth between 1.8 and 2.0 GHz. It is found that choosing configurations that maximizes the separation between the open-end of the PIFAs reduces the mutual coupling.     

Mutual coupling between reduced surface-wave microstrip antennas

An investigation of the mutual coupling between reduced surface-wave microstrip antennas is presented and compared with that for conventional microstrip antennas. Numerical results are presented from a theoretical analysis of the mutual coupling along with confirming experimental results. It is shown that for electrically thin substrates, the space-wave coupling, not the surface-wave coupling, is predominant for typical element spacing, for both the conventional and reduced surface-wave antennas. In addition, the mutual coupling behavior is examined using an asymptotic analysis, which demonstrates how the coupling falls off much faster with patch separation for reduced surface wave antennas compared to conventional microstrip patch antennas     

E-plane coupling between two rectangular microstrip antennas

A model which theoretically characterises end coupling (E-plane coupling) between two rectangular microstrip antennas is discussed. Computer generated S-parameter results for this particular type of mutual coupling are presented.     

Measured mutual coupling between linearly tapered slot antennas

Mutual coupling between two linearly tapered slot antennas arranged in coplanar as well as stacked configurations has been measured. Results indicate that mutual coupling level generally decreases with antenna separations and varies with dielectric constant, and antenna lengths     

Lowest mutual coupling between closely spaced loop antennas

The conditions for zeroing the mutual flux between two closely spaced coil antennas are examined. The analysis is expanded to examine the case of multiple linear antenna coils. Array antennas are used in many areas including magnetic resonance imaging (MRI). Theoretical and experimental results are presented and compared. Good agreement between theory and measurements has been confirmed. A two-dimensional receiving array antenna is proposed     

Genetic approach to the minimization of the coupling between aircraft antennas

In this study, the optimization of the electromagnetic interference (EMI) induced by two aircraft onboard VHF–UHF transreceiver antennas is aimed. The EMI reduction is implemented by varying the antenna positions and orientations. The transreceiver antennas are modelled as single monopole antennas therefore the problem is reduced to antenna-to-antenna coupling optimization. The Method of Moments (MoM) is selected for the EMI analysis and the continuous parameter Genetic Algorithm (CPGA) is chosen for the optimization method. The results of the numerical analysis are verified by the measurement on a 1:10 scaled model in an anechoic chamber.     

Mutual coupling between triangular microstrip antennas on acylindrical body

The full-wave solutions and measured results of mutual coupling coefficients between two cylindrical-triangular microstrip antennas are presented. Both E-plane and H-plane coupling cases are studied. Theory and experiment are in good agreement     

Transmission line model for mutual coupling between microstrip antennas

Although more rigorous treatments have been developed for mutual coupling between microstrip antennas, the purpose of this transmission line model is to provide a numerically efficient substitute for them. Therefore, two approximations have been introduced: first, the surface waves have been neglected and second, each rectangular resonator is replaced by two equivalent radiating slots. In most practical cases the approximations are acceptable; this has been proved while comparing the transmission line model with other published results. It is obvious that the efficieney of the transmission model and can be used to include mutual coupling in practical analysis or synthesis routines for arrays of rectangular microstrip antennas.     

Comparative study on the mutual coupling between different sized cylindrical dielectric resonators antennas and circular microstrip patch antennas

A systematic comparative study on the mutual coupling (S/sub 21/) between dielectric resonator antennas (DRAs) and microstrip patch antennas is presented. The mutual coupling between two cylindrical probe-fed DRAs is studied for different radius to height (a/L) ratios. It is found that the mutual coupling decreases with the radius to height ratio. Comparison between mutual coupling of probe-fed cylindrical DRAs and circular microstrip patch antennas with different dielectric substrates are also studied. The mutual coupling between DRAs is 2 dB stronger than between microstrip patch antennas when the patch is etched on a dielectric substrate of a dielectric constant close to the permittivity of the DRA. The mutual coupling of the circular patch antennas reduces with the dielectric constant of the substrate.