Differential Active Combiner With Bandwidth Peaking to 20 GHz
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Solution Overview
Problem
Designing an ultra wide band active combiner on a die for integrated circuits that spans from DC to greater than 20 GHz is challenging due to the difficulty in achieving gain across the entire frequency band, especially when combining very low level signals, which requires an amplifier stage and poses complex design requirements for both the combiner and amplifier.
Innovation Solution
The solution involves a wideband combiner with a core amplifier and a bandwidth peaking network that includes coils and resistors to increase frequency bandwidth, along with a common mode bias network for voltage bias control, ensuring a substantially constant gain across the frequency range and controlled impedances, allowing for differential input and output signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide band combiner is fabricated on a die for integrated circuit use, then integration is achieved, but achieving ultra wide band gain from DC to over 20 GHz becomes extremely difficult
Solution Approach 1:
The combiner is divided into multiple functional sections: a first combiner section for lower frequencies and a second combiner section for higher frequencies, each optimized for specific frequency ranges. This segmentation allows each section to be designed with appropriate components (inductors, capacitors, resistors) to achieve consistent gain across the entire DC to 20+ GHz band while maintaining IC integration.
Solution Approach 2:
The patent employs parameter changes by varying the values of inductors, capacitors, and resistors in different frequency sections. Specifically, the first combiner section uses different L/C/R parameter values optimized for lower frequencies, while the second section uses different parameters optimized for higher frequencies, enabling consistent performance across the ultra-wide band.
2Power
If an amplifier stage is added to amplify combined low level signals, then signal level is improved, but design complexity increases
Solution Approach 1:
The amplifier function is merged with the combiner structure by incorporating active amplifier elements directly within the combiner circuitry. This integration allows the combiner to provide both signal combining and amplification functions simultaneously, improving output signal level while reducing overall device complexity compared to separate combiner and amplifier stages.
Data Source
AI summary
A wideband combiner includes a core amplifier for receiving first and second pairs of differential input signals and providing a single pair of differential output signals. The pair of differential output signals are a combination of the first and second pair of differential input signals and a signal gain is implemented between the received first and second pairs of differential input signals and the single pair of differential output signals. The core amplifier is configured to provide a gain value between the first and second pairs of differential input signals and the single pair of differential output signals. The signal gain is substantially constant across the frequency bandwidth of the core amplifier. A bandwidth peaking network is coupled to the core amplifier and includes (a) a first coil and a first resistor connected in series and (b) a second coil and a second resistor connected in series.