Quantum mechanics

Sparse array

Algorithm

Engineering

3G MIMO

MIMO

Statistics

Coupling (piping)

Telecommunications

Calibration

Computer science

Antenna (radio)

Beamforming

Mechanical engineering

Physics

Mathematics

Antenna array

Angular resolution (graph drawing)

Electronic engineering

Combinatorics

Direction of arrival

Channel (broadcasting)

Radar

The multiple-input and multiple-output (MIMO) principle is a well-established method to improve the angular resolution of radars. Due to hardware limitations the maximum number of transmit and receive channels is often limited. In order to further increase the angular resolution with a given number of hardware channels, sparse arrays can be employed. However, the optimal placement of the antenna positions is a critical design parameter and it is difficult to consider non-idealities and mutual coupling within the design process. This paper addresses the non-idealities and the influence of coupling on the virtual array positions of a MIMO radar. An efficient calibration method to determine the real antenna positions is proposed. The discrete Fourier transform (DFT) based direction-of-arrival (DoA) estimation is shown with measurements of a 77 GHz and a 160 GHz MIMO radar for a uniform linear array (ULA) and two sparse arrays in comparison.

On the Calibration of mm-Wave MIMO Radars Using Sparse Antenna Arrays for DoA Estimation