Millimeter-Wave Gilbert Mixer Using Negative Transconductance Matching

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Solution Overview

Problem

Existing frequency conversion mixers face challenges in maintaining gain, noise, and linearity for wide bandwidths in millimeter-wave frequencies, particularly in achieving efficient signal processing and signal-to-noise distortion ratio (SNDR) performance.

Innovation Solution

Incorporating a negative resistor, such as a PMOS transistor with a capacitor, into the mixer circuit to enhance impedance matching and reduce transformer loss, thereby improving gain and noise performance while maintaining low power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a conventional mixer circuit is used for frequency conversion, then the circuit structure is simple, but the gain is insufficient and noise performance is poor at millimeter-wave frequencies

Engineering Contradiction:

ImprovegainVSAvoidcircuit structure

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

A negative resistor is introduced as an intermediary component between the transformer and the switching stage. This negative resistor acts as a mediator that compensates for transformer losses and enhances the overall gain without requiring a complete redesign of the mixer architecture, thus improving gain while maintaining reasonable circuit complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the electrical parameters of the circuit by introducing a negative resistance value (negative conductance). This parameter change directly counteracts the positive resistance losses in the transformer and matching network, thereby improving gain and noise performance without fundamentally altering the mixer's structural complexity

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the transformer ratio is increased to improve impedance matching, then impedance matching improves, but transformer loss increases

Engineering Contradiction:

Improveimpedance matchingVSAvoidtransformer loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The negative resistor provides a counteracting effect to the transformer losses. By introducing a negative conductance that opposes the positive resistance losses, the system can achieve better impedance matching without suffering from increased transformer losses, effectively counterbalancing the energy losses

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Use of energy by moving object

If power consumption is reduced for low power operation, then power efficiency improves, but gain and noise performance deteriorate

Engineering Contradiction:

Improvepower consumptionVSAvoidgain

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The negative resistor circuit is designed to provide gain enhancement and noise reduction through its inherent negative conductance property, rather than requiring additional active amplification stages that would consume more power. The circuit uses the negative resistor's self-service capability to improve performance metrics without proportionally increasing power consumption

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20250392258A1Assisted millimeter wave gilbert mixer with a negative transconductance cell

Publication Date: 2025.12.25 APPLE INC

AI summary

A mixer may include a negative resistor, a transformer, a switching stage, and an input stage. The input stage may receive a radio frequency signal and output a current corresponding to a voltage of the radio frequency signal. The switching stage may switch based on a local oscillation signal. The mixer may be a down-conversion mixer that converts high-frequency millimeter-wave signals to an intermediate frequency.