Bottom-Plate Subharmonic Mixer Without LO Frequency Multipliers
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Solution Overview
Problem
Conventional radar systems require mixers that operate at the same frequency as the radar signals, necessitating additional LO frequency multipliers, which increase system footprint and complexity.
Innovation Solution
Implementing a subharmonic mixer that operates with LO signals at a harmonic of the RF input frequency, reducing the need for additional frequency multipliers and enabling a bottom plate mixing arrangement to improve voltage gain and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional mixers operating at the same frequency as radar signals are used, then mixing function is achieved, but additional LO frequency multipliers are required increasing system footprint and complexity
Solution Approach 1:
The patent changes the frequency parameter relationship between LO and RF signals from equal frequency (conventional) to harmonic frequency (subharmonic). The mixer is designed to accept RF signals at a harmonic frequency (e.g., 2nd harmonic) of the LO signal, eliminating the need for frequency multipliers and reducing system complexity while maintaining reliable mixing function
Solution Approach 2:
Instead of using LO frequency multipliers to match the RF frequency (conventional approach), the patent inverts the approach by using an RF frequency that is a harmonic of the LO frequency. This reversal eliminates the multiplier requirement and simplifies the system architecture
2Area of stationary object
If additional LO frequency multipliers are added to achieve proper frequency matching, then mixing accuracy is maintained, but system footprint increases
Solution Approach 1:
The patent changes the frequency parameter relationship from f_RF = f_LO to f_RF = n×f_LO (where n is an integer harmonic). This parameter change eliminates the need for frequency multipliers, reducing system footprint while the harmonic relationship maintains precise frequency matching through the subharmonic mixer's design
3Power
If conventional mixing arrangement is used, then basic mixing function is achieved, but voltage gain and efficiency are limited
Solution Approach 1:
The patent introduces a bottom plate capacitor as an intermediary element in the mixing arrangement. This capacitor couples the RF input to the mixing node, enabling improved voltage gain and efficiency by providing a dedicated impedance transformation path without requiring additional complex circuitry
Solution Approach 2:
The patent transitions from a conventional top-plate mixing arrangement to a bottom-plate mixing arrangement, effectively changing the dimensional configuration of the mixing circuit. This dimensional change in the circuit topology enables improved voltage gain and efficiency while maintaining manageable complexity
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 subharmonic mixer reduces system footprint and complexity by eliminating the need for extra LO frequency multipliers, while enhancing voltage gain and reducing noise, thus improving overall system performance.
Implementation Method 1
a subharmonic mixer configured to receive an RF input signal from a receive antenna that is coupled to the receiver circuitry and configured to receive one or more LO signals from an LO of the transmitter circuitry
Data Source
AI summary
The present disclosure relates to a subharmonic mixer including first and second radio frequency (RF) inputs, local oscillator inputs configured and arranged to receive at least a first, second, third, and fourth local oscillator signals having respective first, second, third, and fourth phases and each having a first frequency, first, second, third, and fourth outputs, a first capacitor coupled between the first RF input and a first node, a first switch coupled between the first node and the second RF input and including a first control terminal to receive the first local oscillator signal, a second switch coupled between the first node and the first output and including a second control terminal to receive the fourth local oscillator signal, and a third switch coupled between the first node and the third output and including a third control terminal to receive the second local oscillator signal.