Phased Array Receiver Optical True Time Delay Beamforming
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Solution Overview
Problem
Phased array antennas face the squint phenomenon when using electronic phase shifters for broadband signals, leading to different frequencies aiming at different angles, and pico and nano cells experience interference due to their size, necessitating improved beam forming techniques for cellular radio access networks.
Innovation Solution
A receiver for phased array antennas utilizing a laser light source with two wavelengths, a wavelength separator, controllable delay units, and a modulator to heterodyne the spectral components, enabling flexible wideband multiple-signal beamforming and reducing interference by independently managing time delays for each antenna element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electronic phase shifters are used at each antenna element to control the viewing angle, then the beam steering capability is achieved, but the squint phenomenon occurs causing different frequencies to aim at different angles
Solution Approach 1:
The patent replaces electronic phase shifters with optical true time delay (TTD) units that use optical path length differences to achieve time delays. This substitution eliminates the frequency-dependent phase shift problem by using optical rather than electronic mechanisms, where the delay is determined by physical path length rather than electronic phase manipulation.
Solution Approach 2:
The patent changes the control parameter from electronic phase shift to optical time delay. By using optical TTD units with controllable delay times, the system achieves beam steering through time-domain manipulation rather than frequency-domain phase manipulation, thereby eliminating the squint phenomenon across broadband frequencies.
2Manufacturing precision
If true-time delays are used to avoid the squint phenomenon, then frequency alignment is improved, but device complexity increases due to additional optical components
Solution Approach 1:
The patent combines multiple functions into integrated optical components. The optical TTD units simultaneously provide time delay, beam steering, and frequency alignment functions. The wavelength separator and combiner merge multiple optical paths into a unified system, reducing the need for separate components for each function.
Solution Approach 2:
The optical TTD units serve multiple purposes: they provide time delay for beam steering, maintain frequency alignment across broadband signals, and enable independent control of each antenna element. The single optical path structure handles both delay and steering functions that would otherwise require separate electronic and mechanical systems.
3Productivity
If pico cells and nano cells are introduced to serve dense populated areas, then data rate and quality of service are improved, but interference between adjacent cells increases
Solution Approach 1:
The patent applies beam forming with independent phase and amplitude control to each radiating element, creating localized beam patterns that can be directed toward specific users while minimizing radiation in other directions. This local control allows adjacent pico/nano cells to operate at high power without interfering with each other, as each cell's energy is focused in its intended service area.
Solution Approach 2:
The system dynamically adjusts the phase and amplitude of each antenna element in real-time to adapt beam patterns to current traffic conditions and user locations. This dynamic beam forming allows the network to optimize performance for each cell independently, reducing interference through spatial separation rather than frequency or time division.
4Object-affected harmful factors
If beam forming is used to control directivity and minimize disturbances, then interference is reduced, but device complexity increases due to individual control of each element
Solution Approach 1:
The patent replaces complex electronic control systems with optical control mechanisms. Optical TTD units and modulators provide precise control of each antenna element's signal in the optical domain, simplifying the control architecture by using optical path manipulation rather than complex electronic phase and amplitude control circuits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively addresses the squint phenomenon and interference issues by providing precise control over the radio beam orientation and directivity, enhancing the performance and cost-effectiveness of phased array antennas, particularly in mobile networks and small cells.
Implementation Method 1
a laser light source arranged to provide an optical spectrum comprising a first spectral component having a first wavelength and a second spectral component having a second wavelength
Implementation Method 2
A wavelength separator configured to separate the first spectral component from the second spectral component, such that the first spectral component is directed onto a first path and the second spectral component is directed onto a second path
Implementation Method 3
A first delay unit is configured to add a controllable time delay to the first spectral component on the first path. A second delay unit configured to add the time delay to the second spectral component on the second path
Implementation Method 4
A modulator configured to modulate the first spectral component on the first path with a received RF signal from the phased array antenna
Implementation Method 5
A heterodyning device configured to heterodyne the resulting first and second spectral components
Data Source
AI summary
A receiver (1) for a phased array antenna comprises a laser light source (2) arranged to provide an optical spectrum comprising a first spectral component having a first wavelength and a second spectral component having a second wavelength. The first wavelength is spaced from the second wavelength. A wavelength separator (4) is configured to separate the first spectral component from the second spectral component, such that the first spectral component is directed onto a first path (A) and the second spectral component is directed onto a second path (B). A first delay unit (16) is configured to add a controllable time delay to the first spectral component on the first path. A second delay unit (42) is configured to add the time delay to the second spectral component on the second path. A modulator (14) is configured to modulate the first spectral component on the first path with a received RF signal from the phased array antenna. A heterodyning device (50) is configured to heterodyne the resulting first and second spectral components.