Integrated LNA Balun and T/R Switch for Low-Loss RF Front Ends
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Solution Overview
Problem
Current wireless communication devices face increased cost and size due to external discrete components in front-end circuit blocks, which also degrade the noise figure and linearity of receivers due to insertion loss in T/R switches and baluns.
Innovation Solution
Implementing a low noise amplifier (LNA) with integrated on-chip combined input matching, balun, and T/R switch, utilizing coupled inductors and tuning capacitors to reduce insertion loss and improve noise figure and linearity, while eliminating the need for external components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If discrete components are used for front-end circuit blocks, then device functionality is achieved, but cost and size increase
Solution Approach 1:
The patent combines multiple discrete front-end circuit blocks (T/R switch, balun, input matching network, and LNA) into a single integrated circuit. The T/R switch, balun, and input matching network are merged with the LNA to form one unified device, eliminating the need for separate external components and reducing overall device size and cost.
Solution Approach 2:
The integrated circuit performs multiple functions simultaneously: the T/R switch enables transmit/receive switching, the balun performs single-ended to differential conversion, the input matching network provides impedance matching, and the LNA amplifies signals. This multi-functional integration reduces the quantity of separate components needed.
2Ease of manufacture
If discrete components are used for front-end circuit blocks, then device functionality is achieved, but noise figure and linearity degrade
Solution Approach 1:
By merging the T/R switch, balun, and input matching network with the LNA into a single integrated circuit, the patent eliminates insertion loss that would occur through multiple discrete component interfaces. This integration improves noise figure and linearity by removing the cumulative losses from separate components.
3Ease of manufacture
If multiple discrete components are used, then circuit functionality is achieved, but insertion loss increases
Solution Approach 1:
The patent integrates the T/R switch, balun, and input matching network directly with the LNA in a single circuit, eliminating the need for multiple external connections and interfaces. This reduces insertion loss by removing the cumulative energy losses that would occur through multiple discrete component boundaries.
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 approach reduces the noise figure, enhances linearity, and decreases the overall size and cost of wireless communication devices by integrating critical circuit functions on-chip, achieving lower insertion loss and improved performance.
Implementation Method 1
a first coupled inductor and a second coupled inductor, each having a first terminal and a second terminal. Each coupled inductor may provide single-ended to differential conversion and/or may provide input matching
Implementation Method 2
a first tuning capacitor coupled to the first coupled inductor and a second tuning capacitor coupled to the second coupled inductor
Data Source
AI summary
A low noise amplifier (LNA) with combined input matching, balun, and/or transmit/receive (T/R) switch is described. In one exemplary design, an apparatus includes a coupled inductor and an LNA. The coupled inductor receives a single-ended input signal, performs single-ended to differential conversion, and provides a differential input signal. The LNA receives and amplifies the differential input signal and provides a differential output signal. The coupled inductor includes magnetically coupled first and second coils. The first coil provides input impedance matching when the LNA is enabled. A resonator circuit formed with the first coil provides high input impedance when the LNA is disabled. A tuning capacitor coupled to the second coil provides amplitude imbalance tuning for the differential input signal. A transmit switch is coupled between the first coil and a transmitter.