Wideband Array Antenna Pattern Control via Frequency-Dependent Time Delays
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Solution Overview
Problem
Current array antenna systems can only control main and side lobe levels and cancellation directions over narrow bandwidths, leading to increased side lobe levels when attempting to create wideband cancellation directions, which is undesirable in applications like radar antennas.
Innovation Solution
A method for controlling the antenna pattern of a wideband array antenna by using a transforming means that affects waveforms between antenna elements and an electronic system with phase shifts or time delays, allowing for the calculation of a weighting function to achieve extended control over the antenna pattern, including the direction, width, and creation of wideband cancellation directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple narrow band cancellation directions are designed around a desired wideband cancellation direction, then a wideband cancellation direction can be created, but the side lobe level is increased
Solution Approach 1:
The patent applies parameter changes by transitioning from fixed time delays to frequency-dependent time delays. The time delay for each antenna element is made a function of frequency, allowing the cancellation direction to be maintained across a wide frequency range without increasing side lobe levels. This is achieved by calculating optimal time delays at multiple frequency points and interpolating between them.
Solution Approach 2:
The patent implements dynamics by making the time delay parameters adaptive and frequency-dependent rather than static. The system dynamically adjusts the time delay for each antenna element based on the operating frequency, enabling the cancellation direction to track accurately across the bandwidth while maintaining low side lobe levels.
2Manufacturing precision
If phase shifters are used to control the antenna pattern, then narrow band control of main lobe and side lobe level is achieved, but wideband control is not possible
Solution Approach 1:
The patent changes the control parameter from phase shift to time delay, and makes this time delay frequency-dependent. This parameter change enables accurate antenna pattern control across wide bandwidths because time delay is a linear phase shift that maintains its effectiveness across frequencies, unlike fixed phase shifters which only work at specific frequencies.
Solution Approach 2:
The patent substitutes traditional phase shifter hardware with a digital signal processing approach using frequency-dependent time delays. This replacement of mechanical/electrical phase shifting components with computational time delay implementation enables wideband operation while maintaining precise control over the antenna pattern.
3Adaptability or versatility
If fixed time delay is used for each antenna element, then wideband main lobe control is achieved, but only narrow band cancellation directions can be created
Solution Approach 1:
The patent changes the time delay parameter from fixed to frequency-dependent for each antenna element. This allows the system to maintain wideband main lobe control while also achieving precise cancellation direction control across the bandwidth, as the frequency-dependent time delays can be optimized for both main lobe steering and cancellation direction placement simultaneously.
Data Source
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AI summary
This invention provides a method to control an antenna pattern of a wideband array antenna wherein a wideband array antenna unit comprising the wideband array antenna and transforming means (100,200) is accomplished. The invention further provides the corresponding wideband array antenna unit and transforming means arranged to control an antenna pattern of an antenna system. The separation between antenna elements in the wideband array antenna can be increased to above one half wavelength of a maximum frequency within a system bandwidth when the array antenna is arranged to operate with an instantaneously wideband waveform.