MIMO Virtual Array Tapering for Sidelobe Reduction
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Solution Overview
Problem
Conventional virtual antenna arrays suffer from high sidelobe amplitudes, which can lead to mistaken target illumination, especially in MIMO radar applications, due to the lack of effective tapering mechanisms suitable for these systems.
Innovation Solution
The implementation of a transceiver with a controller that adjusts the gain of transmit and receive amplifiers using specific window functions, resulting in a virtual array with a defined taper, effectively reducing sidelobe power by increasing the receive array size and applying tailored window functions to both the transmit and receive arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional virtual antenna arrays are used without tapering, then the system structure is simple, but the sidelobe amplitudes are high causing mistaken target illumination
Solution Approach 1:
The patent applies different window functions (first window function for transmit amplifiers, second window function for receive amplifiers) to different parts of the antenna array system. This local differentiation creates a tailored tapering effect that specifically reduces sidelobe amplitudes while maintaining the overall virtual array structure, resolving the contradiction between simple structure and low sidelobes.
Solution Approach 2:
The patent changes the gain parameters of transmit and receive amplifiers by applying window functions. By adjusting these amplitude parameters across different antenna elements, the system achieves effective tapering that reduces sidelobe levels without requiring a complete redesign of the antenna array structure.
2Measurement precision
If the number of receive antennas is increased beyond the conventional ratio, then the angular resolution is improved, but the system complexity and cost increase
Solution Approach 1:
The patent makes the antenna array system multi-functional by applying tapering techniques traditionally used in single-array systems to virtual arrays. This allows the system to achieve enhanced angular resolution through signal processing (window functions) rather than solely through hardware expansion, reducing the need for excessive antenna elements.
Solution Approach 2:
The patent introduces window functions as intermediary processing elements that act on the signals from the antenna array. These window functions serve as a mediator between the raw antenna signals and the final processed output, enabling improved angular resolution through controlled amplitude weighting without directly increasing the physical number of antennas.
3Object-affected harmful factors
If tapering is applied to reduce sidelobes, then the sidelobe power is reduced, but the main beam width may increase
Solution Approach 1:
The patent applies partial tapering through window functions that are designed to provide just enough amplitude weighting to reduce sidelobe power to acceptable levels. By using appropriate window function selections and adjustments, the system achieves sufficient sidelobe suppression without applying excessive tapering that would overly broaden the main beam, thus optimizing the trade-off between these two parameters.
Data Source
AI summary
A transceiver having a virtual array is disclosed that includes a transmit antenna array and a receive antenna array. The transmit antennas are spaced apart by a transmit array spacing. Similarly, the receive antennas are spaced apart by a receive array spacing. One of the receive and transmit arrays has more antenna elements than a ratio of either the transmit array spacing divided by the receive array spacing or of the receive array spacing divided by the transmit array spacing.