How Diodes Make Wireless Amplifiers Clearer
Qualcomm's patent describes a way to make electronic amplifiers, especially for wireless signals, produce clearer sound by using special diodes to adjust how much power they get based on the signal strength.
Original patent title: “Stacked amplifier with diode-based biasing”
Qualcomm's patent describes a way to make electronic amplifiers, especially for wireless signals, produce clearer sound by using special diodes to adjust how much power they get based on the signal strength. Granted to Qualcomm in 2014 with 29 claims and 18 forward citations, and it is expected to expire in 2030.
Coverage
What does this patent actually cover?
This patent describes an amplifier, such as a power amplifier for radio signals (claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 15), that uses several transistors connected in a 'stack' (claim 1). A key component is at least one diode connected in series to a 'gate' of a transistor in this stack (claim 1). This diode provides a 'variable bias voltage' to the transistor. When the amplifier receives a strong input signal (high input power), the diode's voltage drop decreases, which in turn provides a higher bias voltage to the associated transistor (claim 4). This higher bias voltage makes the transistor have 'higher gain' (claim 5), helping the amplifier produce a clearer, more accurate output signal and improving its 'linearity'. For example, this could help a smartphone transmit a clearer signal even when its amplifier is working hard.
The gap
What does this patent NOT cover?
- Amplifiers that do not use transistors arranged in a 'stack' configuration as described in claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1.
- Biasing methods that do not involve a diode providing a variable bias voltage to a transistor in the stack (claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1).
- Diodes that do not specifically exhibit a lower voltage drop at high input power, leading to a higher bias voltage (claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 4).
- Amplifiers where the variable bias voltage does not result in higher gain for the associated transistor at high input power (claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 5).
- Amplifiers where the diode is not coupled in series to a gate of at least one transistor in the stack (claimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1).
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The innovation lies in using the diode's natural characteristic to dynamically adjust the transistor's bias voltage. Specifically, the diode's voltage drop decreases at high input power, which then increases the transistor's bias, leading to higher gain precisely when it's needed most to maintain linearity under demanding conditions.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Smartphone radio frequency (RF) power amplifiers
Cellular base station amplifiers
Wi-Fi routers
Satellite communication systems
Why it matters
The bigger picture
In wireless communication, amplifiers are crucial for boosting signals without distorting them. A 'linear' amplifier means the output signal is a faithful, scaled-up copy of the input, which is essential for clear voice calls and fast data transfer. This patent, assigned to Qualcomm, addresses a fundamental challenge in designing power-efficient and high-quality radio frequency (RF) amplifiers, which are at the heart of mobile phones and other wireless devices.
Filed
February 24, 2010
Granted
September 30, 2014
Market context
Who's building on this
Companies in this space
Qualcomm, the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, is a major developer of chipsets and components for wireless communication, including RF front-end modules and power amplifiers. Other companies like Broadcom, Skyworks Solutions, and Qorvo also design and manufacture RF power amplifiers that could incorporate or build upon similar linearity improvement techniques.
Market impact
This type of innovation allows for more efficient and higher-quality wireless communication. By improving amplifier linearity, it enables devices like smartphones to transmit clearer signals over longer distances or with less power consumption, directly impacting battery life and network performance. It contributes to the ongoing demand for better performance in wireless communication standards.
Claim 1 — Plain English
What this patent covers
This patent describes an amplifier, such as a power amplifier for radio signals (claim 15), that uses several transistors connected in a 'stack' (claim 1). A key component is at least one diode connected in series to a 'gate' of a transistor in this stack (claim 1). This diode provides a 'variable bias voltage' to the transistor. When the amplifier receives a strong input signal (high input power), the diode's voltage drop decreases, which in turn provides a higher bias voltage to the associated transistor (claim 4). This higher bias voltage makes the transistor have 'higher gain' (claim 5), helping the amplifier produce a clearer, more accurate output signal and improving its 'linearity'. For example, this could help a smartphone transmit a clearer signal even when its amplifier is working hard.
The clever bit
The innovation lies in using the diode's natural characteristic to dynamically adjust the transistor's bias voltage. Specifically, the diode's voltage drop decreases at high input power, which then increases the transistor's bias, leading to higher gain precisely when it's needed most to maintain linearity under demanding conditions.
What it does not cover
- Amplifiers that do not use transistors arranged in a 'stack' configuration as described in claim 1.
- Biasing methods that do not involve a diode providing a variable bias voltage to a transistor in the stack (claim 1).
- Diodes that do not specifically exhibit a lower voltage drop at high input power, leading to a higher bias voltage (claim 4).
- Amplifiers where the variable bias voltage does not result in higher gain for the associated transistor at high input power (claim 5).
- Amplifiers where the diode is not coupled in series to a gate of at least one transistor in the stack (claim 1).
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Strong
Citation count
26/40
Moderately cited
Claim breadth
19/20
Very broad protection
Recency
5/20
Granted 10–20 years ago
Assignee scale
20/20
Major company or institution
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$143K – $459K
Midpoint $287K · 3.4 yr remaining · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
29 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Pletcher, N. M., & Zhao, Y. (2014). How Diodes Make Wireless Amplifiers Clearer (U.S. Patent No. 8,847,689). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/8847689/stacked-amplifier-with-diode-based-biasing
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Diodes Make Wireless Amplifiers Clearer cover?
Qualcomm's patent describes a way to make electronic amplifiers, especially for wireless signals, produce clearer sound by using special diodes to adjust how much power they get based on the signal strength.
Who owns patent US 8847689?
Qualcomm owns this patent, granted in 2014.
When does this patent expire?
This patent is expected to expire on February 24, 2030, when the invention enters the public domain.
What is patent US 8847689 cited by?
This patent has been cited by 18 later patents that build on its ideas.
What problem does this patent solve?
In wireless communication, amplifiers are crucial for boosting signals without distorting them. A 'linear' amplifier means the output signal is a faithful, scaled-up copy of the input, which is essential for clear voice calls and fast data transfer. This patent, assigned to Qualcomm, addresses a fundamental challenge in designing power-efficient and high-quality radio frequency (RF) amplifiers, which are at the heart of mobile phones and other wireless devices.
What does this patent NOT cover?
Amplifiers that do not use transistors arranged in a 'stack' configuration as described in claim 1.
Same assignee
More from Qualcomm
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