Phased Array Antenna Cost Reduction via Optical Time Delay
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Solution Overview
Problem
Conventional phased array antennas used in the millimeter wave band require expensive optical components, leading to increased costs due to the need for optical modulators, O/E converters, and other costly optical elements.
Innovation Solution
A phased array antenna configuration that uses a multiplexer to generate a sum signal, an optical modulator to modulate a carrier light beam, a time delay device to impart delays to the signal light beam, and feeding circuits with O/E converters and mixers to convert the delayed signal into radio frequency signals, allowing for beam control without frequency-dependent time delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical means (chromatically dispersive fiber) is used to impart time delay to radio frequency signals in millimeter wave band, then time delay accuracy is improved, but device cost increases due to expensive optical components
Solution Approach 1:
The patent replaces the optical means (chromatically dispersive fiber) with an electrical means (phase shifter) to impart time delay to radio frequency signals. This substitution eliminates the need for expensive optical components while maintaining the beam scanning function in millimeter wave band phased array antennas.
Solution Approach 2:
The patent uses commercially available, low-cost phase shifters instead of expensive optical components. These electrical phase shifters are readily obtainable and significantly reduce the overall device cost while achieving the required time delay accuracy for millimeter wave operations.
2Ease of manufacture
If electrical means (time delay element) is used to impart time delay to radio frequency signals in millimeter wave band, then device cost decreases, but time delay accuracy deteriorates
Solution Approach 1:
The patent changes the operating parameters of the phase shifter to optimize performance for millimeter wave frequencies. By adjusting the electrical characteristics and configuration of the phase shifter, the system achieves both cost-effectiveness and sufficient time delay accuracy for the specific application requirements.
3Adaptability or versatility
If conventional optical components are used in phased array antenna for millimeter wave band, then beam scanning function is achieved, but device complexity increases due to multiple optical components
Solution Approach 1:
The patent extracts and removes the complex optical components (optical modulator, O/E converters, chromatically dispersive fiber) from the phased array antenna system, retaining only the essential electrical phase shifting functionality. This simplification maintains beam scanning capability while dramatically reducing device complexity.
Solution Approach 2:
The patent employs a universal electrical phase shifter that can be integrated directly into the radio frequency signal path, replacing multiple specialized optical components with a single multi-functional electrical device that performs time delay adjustment for beam scanning.
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
This configuration enables a phased array antenna that can operate in the millimeter wave band at a lower cost by using more readily available and affordable optical components, while maintaining the ability to control beam direction without frequency-dependent time delays.
Implementation Method 1
an optical modulator configured to generate a signal light beam SL by carrying out intensity modulation on a carrier light beam CL by use of the sum signal VIF+LO(t)
Implementation Method 2
a time delay device configured to generate delayed signal light beams SL′1, SL′2, . . . and SL′n by imparting time delays Δt1, Δt2, . . . and Δtn to the signal light beam SL
Implementation Method 3
an O/E converter configured to generate a delayed sum signal VIF+LO(t−Δti) by carrying out O/E conversion on the corresponding delayed signal light beam SL′i
Implementation Method 4
a mixer configured to generate the delayed radio frequency signal VRF(t−Δti) by multiplying the delayed intermediate frequency signal VIF(t−Δti) by the delayed local signal VLO(t−Δti)
Data Source
AI summary
Provided is a phased array antenna which can be used in the millimeter wave band and whose cost is lower than that of a conventional phased array antenna. The phased array antenna (1) includes: an optical modulator (OM) configured to generate a signal light beam SL by carrying out intensity modulation on a carrier light beam CL by use of a sum signal VIF+LO(t), the sum signal VIF+LO(t) being obtained by adding an intermediate frequency signal VIF(t) and a local signal VLO(t); and a time delay device (TD) configured to generate delayed signal light beams SL′1, SL′2, . . . and SL′n by imparting time delays Δt1, Δt2, . . . and Δtn to the signal light beam SL. Each feeding circuit (Fi) generates, from a corresponding delayed signal light beam SL′i, a delayed radio frequency signal VRF(t−Δti) to be supplied to an antenna element (Ai).