Microwave Transponder Modulation Without Harmonic Filters
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Solution Overview
Problem
Existing transponder technologies are costly and complex due to the use of non-linear systems like mixers, which generate harmonic lines and require additional filters to remove inessential radiation, leading to bulky and expensive devices.
Innovation Solution
A device for modulating microwave signals using a circuit with a rectified sinusoidal signal to control phase-shifting and variable-gain amplifiers, allowing for single-sideband modulation without harmonic generation, implemented in a transponder with a switch and adder configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If non-linear systems like mixers are used for modulation, then amplitude or phase modulation can be achieved, but harmonic lines are generated requiring additional filters
Solution Approach 1:
The patent extracts and removes the harmful harmonic components generated by non-linear mixing through carefully designed filtering stages. The filter is configured to pass only the desired modulation frequency while blocking harmonic lines, thereby eliminating the complexity issue while maintaining the ease of modulation implementation.
Solution Approach 2:
The patent changes the operating parameters of the modulation system by using specific frequency relationships between the carrier and modulation signals, and by adjusting the filter characteristics to match these parameters. This allows the system to achieve clean modulation without requiring complex multi-stage filtering.
2Reliability
If mixers and filters are used for modulation, then the transponder can reemit modulated signals, but the device becomes bulky and expensive
Solution Approach 1:
The patent merges the modulation function and filtering function into a more integrated architecture. By combining these functions and optimizing their interaction, the system achieves reliable signal modulation while reducing the overall device size and component count, thereby lowering cost and complexity.
Solution Approach 2:
The patent optimizes operational parameters such as the quality factor of resonant circuits and the frequency ratios between signals to achieve efficient modulation with minimal filtering requirements. This parameter optimization reduces the number and size of components needed, making the transponder more compact and cost-effective.
3Object-generated harmful factors
If narrow-band filters are added to remove harmonic lines, then inessential radiation is removed, but the device complexity increases
Solution Approach 1:
The patent selectively extracts and removes only the necessary harmonic components using a precisely designed narrow-band filter. The filter is tuned to pass the fundamental modulation frequency while blocking specific harmonic lines, thereby removing harmful radiation with minimal filtering complexity.
Solution Approach 2:
The patent applies filtering with high selectivity at specific frequency points where harmonics are generated, rather than using broad-band filtering. This localized approach to quality control allows the system to remove harmful radiation efficiently while maintaining simplicity in the overall filter structure.
4Loss of energy
If phase modulation with PSK is used, then the fundamental frequency is suppressed, but harmonics remain requiring complex filters
Solution Approach 1:
The patent extracts and removes the remaining harmonic components that persist after phase modulation by using a targeted filtering approach. The filter is designed to pass the suppressed fundamental frequency while blocking the harmonic lines, achieving energy efficiency without requiring complex multi-stage filtering.
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 enables low-cost, high-performance transponders that eliminate harmonic lines and carrier frequencies, reducing the need for filters and simplifying the device architecture, resulting in a more efficient and cost-effective localization system.
Implementation Method 1
a variable-gain amplifier the gain of which is controlled by said rectified sinusoidal signal
Implementation Method 2
a phase-shifting circuit able to receive as input said microwave signal comprising: a first channel applying a given phase shift; a second channel applying said given phase shift increased by π
Implementation Method 3
a circuit for generating a rectified sinusoidal signal
Data Source
AI summary
The modulation includes in amplifying the microwave signal phase shifted by a given angle into a first sinusoidal signal, in order to obtain a first amplified signal; and in amplifying the microwave signal phase shifted by the given angle increased by π into a second sinusoidal signal phase shifted by π with respect to the first signal, in order to obtain a second amplified signal phase shifted by π with respect to the first amplified signal; the modulated microwave signal being the sum of the first amplified signal and the second amplified signal.