Series-Fed Array Capacitive Coupling for Stable Impedance Matching
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Solution Overview
Problem
Imbalanced power distribution in phased array antenna systems leads to signal degradation, reduced efficiency, and undesired sidelobes due to variations in input capacitance caused by temperature or environmental factors, affecting impedance matching and signal quality.
Innovation Solution
A series-fed array system with capacitors disposed in the feed path between tap points and high-input-impedance array elements to stabilize input capacitance, ensuring uniform LC products and impedance matching across elements, thereby reducing the impact of temperature and environmental variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct connection between tap points and array elements is used, then device complexity is reduced, but input capacitance varies with temperature causing impedance mismatch and signal degradation
Solution Approach 1:
A capacitor is introduced as an intermediary component between the tap point and the array element input terminal. This capacitor acts as a mediator that decouples the temperature-dependent input capacitance of the array element from the feed path, thereby stabilizing the impedance matching condition across temperature variations while maintaining a relatively simple feed structure.
Solution Approach 2:
The invention changes the electrical parameter (capacitance) of the feed path by introducing a capacitor with specific capacitance value. This parameter change compensates for the temperature-induced variations in input capacitance of the array element, ensuring stable impedance matching. The capacitor value is selected to be appropriate relative to the input capacitance of the array element to achieve optimal compensation.
2Adaptability or versatility
If input capacitance of array elements varies with temperature, then adaptability to environmental conditions is improved, but power distribution balance deteriorates causing signal degradation and sidelobes
Solution Approach 1:
The capacitor serves as an intermediary that isolates the temperature-sensitive input capacitance of the array element from the power distribution network. By placing the capacitor in series between the tap point and the array element, it prevents temperature-induced capacitance variations from affecting the power distribution balance, thereby maintaining efficient power delivery and reducing energy loss.
Solution Approach 2:
The capacitor is configured to preemptively counteract the harmful effects of temperature-induced capacitance variations. By selecting an appropriate capacitance value, the system pre-compensates for the expected range of input capacitance changes, preventing power distribution imbalance before it occurs and thereby avoiding signal degradation and unwanted sidelobes.
3Reliability
If capacitor with small capacitance value is used, then impedance matching stability is improved, but signal transmission capability may be reduced
Solution Approach 1:
The invention optimizes the capacitance parameter by selecting a specific value range. The capacitance is chosen to be small enough to effectively decouple temperature variations and stabilize impedance matching, yet large enough to maintain adequate signal transmission capability. This parameter optimization achieves a balance between stability and transmission performance.
Solution Approach 2:
The capacitor introduces localized capacitance at the input terminal of each array element, creating a locally optimized condition for impedance matching. This local quality adjustment allows each element to maintain consistent input impedance regardless of temperature, while the overall signal transmission capability is preserved through proper capacitance value selection.
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 system achieves stable impedance matching and high-quality signal transmission by minimizing capacitance variations, resulting in improved return and insertion loss characteristics and enhanced transmission efficiency.
Implementation Method 1
The N capacitors are arranged to capacitively couple the N tap points to the N gates of the N transistors, respectively, to provide the N voltage signals
Data Source
AI summary
An array system for signal transmission includes a transmission line, N array elements and N capacitors. The transmission line includes N tap points. The N array elements are configured to be driven by N voltage signals fed to N input terminals of the N array elements respectively. Each array element includes a transistor, and N gates of N transistors in the N array elements serves as the N input terminals respectively. The N capacitors are arranged to capacitively couple the N tap points to the N gates of the N transistors, respectively, to provide the N voltage signals. Capacitance of each capacitor is less than input capacitance at a gate of a corresponding transistor coupled to the capacitor.