Subharmonic Mixer Layout 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 the 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

VSEngineering Contradiction Analysis

1Device complexity

If conventional mixers operating at the same frequency as radar signals are used, then signal mixing can be achieved, but additional LO frequency multipliers are required, increasing system footprint and complexity

Engineering Contradiction:
Improvesystem complexityVSAvoidsignal mixing capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the operating parameter of the mixer from requiring LO frequency equal to RF frequency to accepting LO frequency at a harmonic (e.g., half) of the RF frequency. This parameter change eliminates the need for LO frequency multipliers, reducing system complexity and footprint while maintaining signal mixing capability through subharmonic mixing operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and eliminates the LO frequency multiplier components from the system by using a subharmonic mixer that directly accepts harmonic LO signals. This removal of unnecessary components reduces system footprint, complexity, and potential failure points while preserving the essential signal mixing function

Inventive Principle:
Principle #2Taking out (Extraction)

2Area of stationary object

If additional LO frequency multipliers are included in the system, then the mixer can operate at the correct frequency, but the system footprint and complexity increase

Engineering Contradiction:
Improvesystem footprintVSAvoidsystem complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent removes the LO frequency multiplier components from the system architecture by employing a subharmonic mixer that natively accepts harmonic LO frequencies. This extraction eliminates the physical components that would occupy space and add complexity, directly reducing system footprint and simplifying the overall design

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the LO signal generation and mixing functions more closely by allowing the mixer to directly process harmonic LO signals without intermediate frequency multiplication stages. This consolidation reduces the number of discrete components and interconnections, thereby reducing system footprint and complexity

Inventive Principle:
Principle #5Merging (Combining)

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

Methodology Applied
Scientific EffectMixing: Heterodyne

Data Source

PatentEP4686092A1Subharmonic mixer
Publication Date: 2026.01.28 NXP BV
  • EP4686092A1 patent drawingFigure 1
  • EP4686092A1 patent drawingFigure 2
  • EP4686092A1 patent drawingFigure 3

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.