Describes the modeling of a 77 GHz 2 X 4 antenna array for Frequency-Modulated Continuous-Wave (FMCW))applications. The presence of antennas and antenna arrays in and around vehicles has become a commonplace with the introduction of wireless collision detection, collision avoidance, and lane departure warning systems. The two frequency bands considered for such systems are centered around 24 GHz and 77 GHz, respectively. In this example, we will investigate the microstrip patch antenna as a phased array radiator. The dielectric substrate is air.

How the antenna mutual coupling affects the performance of an orthogonal space-time block code (OSTBC) transmission over a multiple-input multiple-output (MIMO) channel. The transmitter and receiver have two dipole antenna elements each. The BER vs. SNR curves are plotted under different correlation and coupling scenarios. To run this example, you need Antenna Toolbox™.

A switched beam array of 4 resonant dipoles. The beam switching is accomplished by using a 4 X 4 Butler matrix. The effect of the beam switching is shown by observing the outputs of 4 receiving antennas that are placed in the far-field of the array at the approximate azimuthal angles corresponding to the beam peaks. The effect of mutual coupling between the array elements on the transmit side is accounted for using S-parameters.

Analyzes a 2-antenna diversity scheme to understand the effect that position, orientation and frequency have on received signals. The analysis is performed under the assumptions that impedance matching is not achieved and mutual coupling is taken into account [1].

Uses infinite array analysis to model large finite arrays. The infinite array analysis on the unit cell reveals the scan impedance behavior at a particular frequency. This information is used with the knowledge of the isolated element pattern and impedance to calculate the scan element pattern. The large finite array is then modeled using the assumption that every element in the array possesses the same scan element pattern. The real array of finite size can be analyzed using the embedded element pattern as a next step. This approach is presented in Modeling Mutual Coupling in Large Arrays Using Embedded Element Pattern.

Demonstrates the embedded element pattern approach to model large finite arrays. Such an approach is only good for very large arrays so that the edge effects may be ignored. It is common to consider an infinite array analysis as a first step for such kind of analysis. This approach is presented in Modeling Mutual Coupling in Large Arrays Using Infinite Array Analysis; Modeling Mutual Coupling in Large Arrays Using Infinite Array Analysis>. The embedded element pattern refers to the pattern of a single element embedded in the finite array, that is calculated by driving the central element in the array and terminating all other elements into a reference impedance [1]-[3]. The pattern of the driven element, referred to as the embedded element, incorporates the effect of coupling with the neighboring elements. It is common to choose the central region/element of the array for the embedded element, depending on whether the array has an even or odd number of elements(for large arrays it does not matter). The pattern of the isolated element (the radiator located in space by itself) changes when it is placed in an array due to the presence of mutual coupling. This invalidates the use of pattern multiplication, which assumes that all elements have the same pattern. To use pattern multiplication to calculate the total array radiation pattern, and improve the fidelity of the analysis, we replace the isolated element pattern with the embedded element pattern.

The far-field radiation pattern of a fully excited array can be recreated from the superposition of the individual embedded patterns of each element. The pattern multiplication theorem in array theory states that the far-field radiation pattern of an array is the product of the individual element pattern and the array factor. In the presence of mutual coupling, the individual element patterns are not identical and therefore invalidates the result from pattern multiplication. However, by computing the embedded pattern for each element and using superposition, we can show the equivalence to the array pattern under full excitation.