On-Chip Balun Circuit With Split Antenna Windings
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Solution Overview
Problem
Existing on-chip antenna switch circuits face challenges in power handling due to parasitic diodes rectifying RF transmitter signals, leading to DC voltage dissipation and limited transmitter power, especially in deep-submicron CMOS technology, which restricts the integration of antenna switches within the chip.
Innovation Solution
The integration of a balun circuit with a split antenna winding and AC coupling capacitors, positioning the antenna switches in the ground path and using coupling capacitors to prevent rectification, allowing for efficient power handling and fast switching between antennas while maintaining low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If antenna switches are integrated within the chip in deep-submicron CMOS technology, then device integration and miniaturization are improved, but parasitic diodes rectify RF transmitter signals causing DC voltage dissipation and limiting transmitter power
Solution Approach 1:
The antenna switching circuit is divided into separate functional blocks: RF switches for antenna selection, a balun circuit for impedance transformation, and AC coupling capacitors for DC blocking. This segmentation allows each component to be optimized independently, enabling chip integration while managing power dissipation through proper signal coupling.
Solution Approach 2:
AC coupling capacitors are introduced as intermediary elements between the antenna switches and the balun circuit. These capacitors block DC voltage while allowing RF signals to pass, preventing rectification effects and enabling both integrated design and adequate transmitter power handling.
2Ease of manufacture
If parasitic diodes are present in antenna switches, then device fabrication is simplified, but rectification of RF signals occurs leading to DC voltage dissipation
Solution Approach 1:
AC coupling capacitors serve as intermediary elements that block DC voltage paths created by parasitic diodes while maintaining RF signal transmission. This allows the use of standard CMOS switches with parasitic diodes without suffering from rectification effects, as the capacitors prevent DC buildup.
Solution Approach 2:
The DC component is extracted or removed from the signal path using AC coupling capacitors, separating the DC blocking function from the RF switching function. This allows the parasitic diodes to remain in the switches without causing harmful rectification effects.
3Power
If balun circuit with split antenna winding is used, then power handling capability is improved, but device complexity increases
Solution Approach 1:
The balun circuit is designed to perform multiple functions: impedance transformation between differential and single-ended ports, signal balancing, and power division. By integrating these functions into a single circuit block with split windings, the design achieves improved power handling without proportionally increasing overall system complexity.
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 solution enables effective power handling and fast switching between antennas with minimal insertion loss and improved isolation, suitable for ultra-low power sensor networks and wireless applications, while maintaining a low silicon area and cost.
Implementation Method 1
The first antenna loop, the second antenna loop, and the transceiver loop are coaxially positioned such that the first antenna loop and the second antenna loop are coupled in opposite phase to the transceiver loop
Data Source
AI summary
Balun circuitry with a transceiver loop, a first antenna loop, and a second antenna loop is disclosed. The first antenna loop, the second antenna loop, and the transceiver loop are coaxially positioned such that the first antenna loop and the second antenna loop are coupled in opposite phase to the transceiver loop. In at least one exemplary embodiment, a semiconductor substrate has a layer that includes the first antenna loop, the second antenna loop, and the transceiver loop.