UWB RF Filter-Amplifier Circuit for High SFDR Signal Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RF signal generators are unable to produce ultra-wide band (UWB) RF signals with a high spurious-free dynamic range (SFDR) of −80 dBc or higher, which is required for testing 5G wireless communication network devices like RF integrated circuits and analog-to-digital converters with high data rates.
Innovation Solution
A radio frequency (RF) signal filter and amplification circuit using solid-state RF switches and surface-mount low noise amplifiers, with multiple signal paths and band pass filters, to selectively amplify and isolate the carrier signal while suppressing spurious signals, achieving a high SFDR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromechanical RF switches are used in filter circuits, then sufficient isolation can be achieved, but the device complexity, cost, and switching speed are adversely affected
Solution Approach 1:
The patent replaces electromechanical RF switches with solid-state RF switches in the filter circuit. This substitution eliminates moving parts, reducing device complexity and improving reliability while maintaining the necessary isolation performance through solid-state switching mechanisms.
Solution Approach 2:
The patent changes the isolation mechanism from mechanical contact-based isolation to electrical parameter-based isolation using solid-state switches. The solid-state switches provide sufficient isolation through their electrical characteristics rather than physical separation, thereby simplifying the overall device structure.
2Reliability
If electromechanical RF switches are used in filter circuits, then sufficient isolation can be achieved, but the manufacturing cost is increased
Solution Approach 1:
The patent replaces electromechanical RF switches with solid-state RF switches, which are generally less expensive to manufacture and assemble. Solid-state components eliminate the need for precision mechanical assemblies, reducing manufacturing complexity and cost while maintaining isolation performance.
Solution Approach 2:
The patent adopts solid-state switches that are cheaper and more readily available than electromechanical switches. While solid-state switches have different lifecycle characteristics, their lower unit cost and ease of replacement make them economically advantageous for achieving the required isolation.
3Reliability
If electromechanical RF switches are used in filter circuits, then sufficient isolation can be achieved, but the switching speed is reduced
Solution Approach 1:
The patent replaces electromechanical RF switches with solid-state RF switches, which have no moving parts and can switch states extremely rapidly. Solid-state switching occurs on the order of nanoseconds or picoseconds, compared to the milliseconds or microseconds required for mechanical movement, thereby dramatically improving switching speed while maintaining isolation.
4Productivity
If existing RF signal generators are used, then basic RF signal generation is achieved, but the spurious-free dynamic range is insufficient for 5G device testing
Solution Approach 1:
The patent segments the RF signal generation process into multiple parallel filter paths, each tuned to different frequency bands. By dividing the signal path and selectively filtering spurious signals in each segment, the system achieves high SFDR performance that cannot be obtained from a single undivided signal path.
Solution Approach 2:
The patent introduces an intermediary filter circuit between the RF signal generator and the test device. This intermediary system includes multiple band-pass filters and solid-state switches that selectively remove spurious signals while passing the desired carrier signal, thereby improving the SFDR of the output signal.
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 solution effectively increases the spurious-free dynamic range of RF signals to −80 dBc or higher, addressing the limitations of electromechanical switches by using solid-state components, reducing costs, and improving switching speed and noise levels.
Implementation Method 1
Each of these signal paths can include an amplifier and a band pass filter connected in series between a corresponding first output of the first RF switch and a corresponding second input of the second RF switch
Implementation Method 2
the amplifier in the selected signal path is enabled and provides amplification and some amount of isolation
Data Source
AI summary
Disclosed is a filter and amplification circuit including a first switch with a single input and multiple outputs, a second switch with multiple inputs and a single output, and signal paths (each with an amplifier and band pass filter) between the outputs of the first switch and the inputs of the second switch, respectively. During filtering, the input of the first switch receives a radio frequency (RF) signal and filtering is performed through a combination of a selected signal path (which is active and has its amplifier enabled) and non-selected signal paths (which are passively coupled to the selected signal path and have their amplifiers disabled). Isolation is provided by the switches (e.g., solid-state switches) and the amplifiers, ensuring that the filtered RF signal at the single output of the second switch has a desired high spurious-free dynamic range (SFDR). Also disclosed are a test system and associated methods.