Multiple-Coil Transimpedance LNA Without Precision Capacitors
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Solution Overview
Problem
Existing low noise amplifiers for high frequency radio frequencies, particularly in the millimeter wave domain, face challenges due to the difficulty in achieving high precision with capacitors, which are sensitive to production process variations and require large surface area, leading to inefficiencies in bandwidth and power consumption.
Innovation Solution
A multiple coil low noise amplifier design utilizing transimpedance stages with magnetically coupled inductors, eliminating the need for capacitors and reducing surface area requirements, while maintaining sufficient gain and operational bandwidth through feedback loops involving voltage-to-voltage, voltage-to-current, current-to-voltage, and current-to-current transformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If capacitors are used in resonators to generate sufficient gain, then gain compensation is achieved, but manufacturing precision becomes difficult to obtain and surface area increases
Solution Approach 1:
The patent removes capacitors from the resonator circuit and replaces them entirely with inductors (coils). This extraction eliminates the manufacturing precision problems associated with capacitors while maintaining the resonant functionality through inductive coupling between coils.
Solution Approach 2:
The patent changes the fundamental parameter from capacitive resonance to inductive resonance. By using inductors with carefully controlled inductance values and mutual inductance coupling, the system achieves the same gain compensation function without relying on capacitor precision.
2Power
If capacitors are used in resonators, then gain compensation is achieved, but surface area increases
Solution Approach 1:
By extracting capacitors from the circuit and replacing them with inductors, the patent reduces the surface area required. Inductors can be implemented as compact spiral or meander patterns on the PCB, occupying less space than the large surface area capacitors would require.
3Adaptability or versatility
If multiple stages are used for gain compensation, then bandwidth is increased, but device complexity increases
Solution Approach 1:
The patent combines multiple resonant circuits with different resonant frequencies into a single amplifier stage. The inductively coupled coils create multiple resonant modes that collectively provide wide bandwidth gain compensation, eliminating the need for separate amplifier stages.
Solution Approach 2:
The inductor-based resonator system performs multiple functions simultaneously: it provides impedance matching, frequency selection, and gain compensation across a wide bandwidth. This multi-functionality reduces the overall device complexity compared to multi-stage amplifiers.
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 design achieves a wide bandwidth with reduced power consumption and improved robustness against production process variations, eliminating the need for precise capacitors and minimizing gain tilt, thus enhancing amplifier performance.
Implementation Method 1
a second coil inductively coupled to the first coil
Implementation Method 2
a fourth coil inductively coupled to the third coil
Data Source
AI summary
A multiple coil low noise amplifier with transimpedance is described for high frequency radio. In an example, an amplifier includes a first coil electrically coupled to an input node of an amplifier, configured to provide an input to the input node, a second coil inductively coupled to the first coil and electrically coupled to a ground node of the amplifier, configured to ground the amplifier, a third coil electrically coupled to an output node of the amplifier and to ground, configured to filter an amplifier output at the node, and a fourth coil inductively coupled to the third coil and electrically coupled to the output node, configured to provide the amplifier output.