Push-Push Oscillator Phased Arrays Without T/R Phase Shifters
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Solution Overview
Problem
Conventional phased array antenna T/R modules for high-definition imaging radars are complex, costly, and heavy due to the presence of phase shifters, which cause power loss and reduce efficiency, and have high production costs and weight due to the need for expensive components and multi-stage amplifiers.
Innovation Solution
The implementation of injection locked push-push oscillator circuits within the T/R modules, which eliminate the phase shifter and reduce the amplification chain, allowing for direct down conversion and partitioning the total phase shift among multiple push-push oscillator levels, thereby simplifying the system and improving linearity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional phase shifters are used in T/R modules, then phase control is achieved, but power loss increases and efficiency decreases
Solution Approach 1:
The patent removes the phase shifter component entirely from the T/R module architecture. Instead of using a phase shifter to control beam direction, the invention uses push-push oscillators that inherently generate signals with different phases (0度和180度) to drive adjacent antenna elements, achieving phase control without the power-lossy phase shifter component.
Solution Approach 2:
The push-push oscillator serves multiple functions simultaneously: it generates the carrier signal, provides frequency multiplication, and creates the necessary phase differences for beam steering. This multi-functional approach eliminates the need for separate phase shifter and frequency multiplier components, reducing overall system complexity and power loss.
2Ease of manufacture
If phase shifters are included in T/R modules, then phase adjustment is possible, but production cost increases
Solution Approach 1:
By extracting and removing the phase shifter component from the T/R module, the patent significantly reduces the bill of materials and assembly complexity. The simplified architecture with fewer components directly translates to lower production costs and easier manufacturing.
3Manufacturing precision
If phase shifters are used for beam steering, then phase control is achieved, but phase linearity versus frequency deteriorates
Solution Approach 1:
Removing the phase shifter eliminates the source of non-linear phase response. The push-push oscillator architecture provides inherently linear phase characteristics across the operating bandwidth, improving beam focus precision without frequency-dependent degradation.
4Power
If conventional receiving path with multiple stages is used, then signal amplification is achieved, but system size and weight increase
Solution Approach 1:
The patent combines the functions of multiple amplification stages into a single low-noise amplifier (LNA) in the receiving path. This consolidation maintains the necessary signal amplification while significantly reducing the weight and volume of the receiving subsystem.
5Power
If multi-stage amplification chain is used in receiver, then signal strength is increased, but third harmonic intercept point decreases
Solution Approach 1:
By consolidating amplification into a single LNA stage rather than using multiple stages, the patent reduces the accumulation of non-linear effects and harmonic distortion. The single-stage approach maintains signal strength while preserving better linearity characteristics and higher third harmonic intercept point.
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 solution reduces the production cost, size, and weight of the radar system, enhances phase scan capabilities, and improves the third harmonic intercept point by eliminating the phase shifter and using simpler, cheaper components, while maintaining signal stability and noise characteristics.
Implementation Method 1
a cascade of at least one (three, in the illustrated embodiment) injection locked push-push oscillators 15, 20 and 30 each receiving a signal at a given frequency and delivering a signal at an even multiple of the frequency of the injected signal
Implementation Method 2
injection locked push-push oscillators 15, 20 and 30 each receiving a signal at a given frequency and delivering a signal at an even multiple of the frequency of the injected signal (twice the incoming frequency in the illustrated embodiment)
Data Source
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AI summary
The present invention relates to a radar imaging apparatus comprising: a reference signal generator comprising a quartz oscillator and at least one level of first push-push oscillators cascaded with the quartz oscillator; a phased array antenna including at least one transmitter/receiver module comprising at least one level of second push-push oscillators; and a radiating apparatus cascaded with the reference signal generator and with at least one transmitter/receiver module, wherein each second push-push oscillator is configured to receive an injecting RF signal and to multiply its frequency by a factor of 2*N, where N is an integer, thereby changing the phase of the injecting RF signal.