Balanced Frequency Quadrupler Using Quadrature-Coupled Doublers
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Solution Overview
Problem
Existing frequency multipliers face challenges in efficiently generating high-frequency millimeter and submillimeter-wave signals due to complex circuit designs required for higher-order harmonics, leading to low efficiency and power handling issues, especially when cascaded, as they struggle with reflected power and intermediate frequency components.
Innovation Solution
A novel frequency quadrupler circuit architecture utilizing a hybrid coupler to drive balanced doublers in phase quadrature and an integrated anti-series diode pair, which addresses power reflection and harmonic separation issues, enabling a unilateral network that reduces loading effects and eliminates the need for filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If cascaded chains of doublers and triplers are used to generate high-frequency signals, then the desired output frequency is achieved, but the overall efficiency drops substantially below 1% due to low efficiency at each stage
Solution Approach 1:
The invention segments the frequency multiplication function into two independent parallel paths: an even-order harmonic path and an odd-order harmonic path. Each path processes specific harmonics separately, avoiding the need for cascaded stages and intermediate matching networks, thereby eliminating cumulative efficiency losses across multiple stages.
Solution Approach 2:
The invention introduces a new dimensional approach by separating harmonics into two independent processing dimensions (even-order and odd-order paths) rather than sequentially cascading stages. This dimensional separation allows simultaneous processing of different harmonics without intermediate losses.
2Reliability
If intermediate matching stages are inserted between multiplier stages to optimize impedance, then impedance matching is improved, but device complexity and system loss increase
Solution Approach 1:
The invention extracts and removes the intermediate matching stages from the multiplier chain entirely. By separating even and odd order harmonics into independent paths, the design eliminates the need for intermediate matching networks, reducing complexity and loss while maintaining reliable impedance matching at each stage.
3Reliability
If isolators are used between multiplier stages to reduce loading effects, then stage isolation is improved, but overall efficiency decreases due to additional losses
Solution Approach 1:
The invention segments the harmonic paths independently, with even-order and odd-order harmonics processed through separate parallel circuits. This segmentation provides inherent isolation between stages without requiring additional isolators, as each path is self-contained and does not load the other.
4Power
If input stages are designed to handle high power (several watts) to overcome low efficiencies, then usable output power is achieved, but power handling requirements and device stress increase
Solution Approach 1:
The invention segments the power amplification function across two parallel paths that process even and odd harmonics simultaneously. This segmentation distributes the power handling requirements more efficiently, avoiding the need for single stages to handle excessive power levels, thereby reducing device stress while maintaining high output power.
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 architecture achieves higher-order direct quadruplers with improved efficiency and power output, maintaining performance across cascaded stages by canceling reflected power and naturally separating harmonics, resulting in efficient generation of high-frequency signals up to 160 GHz with enhanced power handling.
Implementation Method 1
A novel frequency quadrupler circuit architecture utilizing a hybrid coupler to drive balanced doublers in phase quadrature
Implementation Method 2
These components are based on a nonlinear device, typically a Schottky diode, that is driven with a low frequency, high-power source. The nonlinearities of the device produces harmonics of this input
Implementation Method 3
balanced doubler and tripler configurations that employ anti-parallel or anti-series connected diodes. These circuit configurations have become commonplace due to their inherent isolation of even-order and odd-order harmonics, eliminating the need for filters.
Data Source
AI summary
An integrated frequency quadruplet consists of a pair of balanced frequency doublers that are driven in phase quadrature using a hybrid coupler. This approach results, effectively, in a “unilateral” multiplier that presents a match to the input-driving source, irrespective of the impedance of the doubler stages. The present invention applies this architecture to implement an integrated frequency quadruplet with output frequency of 160 GHz using quasi vertical GaAs varactors fabricated on thin silicon support membranes. The quadruplet has a balanced circuit architecture that addresses degradation issues often arising from impedance mis-matches between multiplier stages. A unique quasi-vertical diode process is used to implement the quadruplet, resulting in an integrated drop-in chip module that incorporates 18 varactors, matching networks and beamleads for mounting. The chip is tailored to fit a multiplier waveguide housing resulting in high reproducibility and consistency in manufacture and performance.