Switchable Multiband Balun for Compact Multi-Frequency RF Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing baluns, such as Marchand baluns, face challenges in supporting multiple frequency bands without increasing circuit area, which is necessary for miniaturization in 5G and Beyond 5G applications.
Innovation Solution
A multiband balun design that includes a first and second balanced line, an unbalanced line, and a switch that can change the unbalanced termination between an open and ground state, allowing operation as either a Marchand or transformer type balun, with optional line length adjustment to support multiple frequency bands without increasing circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a band variable filter technology with switching elements is applied to make coupled line length variable for multiband operation, then the balun can support multiple frequency bands, but the circuit area increases due to adding new coupled lines
Solution Approach 1:
The patent applies dynamics by making the coupled line length variable through switching elements. The first and second switching elements can connect or disconnect the third and fourth coupled lines, respectively, allowing the effective coupled line length to be dynamically adjusted between different lengths to support multiple frequency bands while maintaining a compact circuit area.
Solution Approach 2:
The patent changes the electrical parameters of the balun by varying the coupled line length through switching. By controlling the switching elements to connect or disconnect specific coupled lines, the electrical length and characteristic impedance are adjusted, enabling the balun to operate at different center frequencies for multiband applications without increasing the physical circuit area.
2Adaptability or versatility
If the coupled line length is made variable to support multiple bandwidths, then the balun can handle signals of multiple frequency bands, but additional circuit space is required
Solution Approach 1:
The patent implements dynamic configuration of the coupled lines using switching elements. The switching elements enable the coupled line structure to be reconfigured between different effective lengths, allowing the balun to adapt its bandwidth and center frequency while maintaining a fixed, compact physical footprint.
Solution Approach 2:
The patent achieves multi-functionality by designing the coupled line structure with switching elements that allow the same physical circuit to perform multiple functions - operating as a balun with different center frequencies and bandwidths by simply changing the switching state, eliminating the need for separate circuits for each frequency band.
3Adaptability or versatility
If new coupled lines are added to make the coupled line length variable, then the center frequency can be changed, but the circuit area becomes larger
Solution Approach 1:
The patent uses switching elements to dynamically adjust the effective length of the coupled lines. The first switching element controls connection to the third coupled line, and the second switching element controls connection to the fourth coupled line, allowing the center frequency to be varied by changing which coupled lines are active without adding permanent additional circuit area.
Solution Approach 2:
The patent changes the electrical parameters (length and impedance) of the coupled lines by selectively connecting or disconnecting them through switching elements. This allows the center frequency to be adjusted by modifying the effective electrical length of the coupled line structure without increasing the physical circuit area.
Data Source
AI summary
A multiband balun includes a first balanced line, one end of the first balanced line being grounded and an other end of the first balanced line being connected to a balanced terminal, the balanced terminal being connected to a balanced circuit; a second balanced line, one end of the second balanced line being grounded and an other end of the second balanced line being connected to a balanced terminal, the balanced terminal being connected to the balanced circuit; an unbalanced line, one end of the unbalanced line being connected to an unbalanced terminal, the unbalanced terminal being connected to an unbalanced circuit; and a first switch, wherein the first switch switches a state of an unbalanced termination to one of an open state and a ground state and the unbalanced termination is one end of the unbalanced line opposite the one end connected to the unbalanced terminal.