Electromagnetic imaging device for active microwave and millimeter wave security inspection apparatus

An electromagnetic imaging device for an active microwave and millimeter wave security inspection apparatus, comprising;

• a two-dimensional multiple-input multiple-output array panel comprising a plurality of two-dimensional multiple-input multiple-output sub-arrays, wherein each two-dimensional multiple-input multiple-output sub-array of the plurality of two-dimensional multiple-input multiple-output sub-array comprises a plurality of transmitting antennas arranged linearly and a plurality of receiving antennas arranged linearly, the plurality of transmitting antennas arranged linearly being intersected with the plurality of receiving antennas arranged linearly, the plurality of transmitting antennas are configured to emit an electromagnetic wave with a specific frequency, and the plurality of receiving antennas are configured to receive an electromagnetic wave reflected from an inspected object;
• a signal processing device configured to reconstruct an image of the inspected object based on the electromagnetic wave received by the plurality of receiving antennas;
• a display device configured to display the image of the inspected object;
• and
• a ranging radar arranged on the two-dimensional multiple-input multiple-output array panel and configured to accurately measure a distance between the inspected object and the electromagnetic imaging device,
• wherein, in each sub-array, a midpoint of a connection line between each transmitting antenna of the plurality of transmitting antennas and a corresponding receiving antenna of the plurality of receiving antennas serves as a virtual equivalent phase center of a pair of the each transmitting antenna and the corresponding receiving antenna, and the plurality of transmitting antennas and the plurality of receiving antennas are arranged to generate an equivalent phase center web;
• wherein a distance between adjacent transmitting antennas of the plurality of transmitting antennas or a distance between adjacent receiving antennas of the plurality of receiving antennas is equal to a wavelength of the electromagnetic wave with the specific frequency, and a distance between adjacent equivalent phase centers in the equivalent phase center web generated ranges from 30% to 70% of the wavelength of the electromagnetic wave with the specific frequency;
• and
• wherein the two-dimensional multiple-input multiple-output array panel has a shape of rectangle, and each sub-array comprises a row of transmitting antennas arranged in a first diagonal direction of the two-dimensional multiple-input multiple-output array panel and a row of receiving antennas arranged in a second diagonal direction of the two-dimensional multiple-input multiple-output array panel, and the row of transmitting antennas intersects with the row of receiving antennas;
• wherein the plurality of two-dimensional multiple-input multiple-output sub-arrays are arranged in a non-overlapping array.