Radial PCB Coupler for Compact Interlayer RF Coupling
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Solution Overview
Problem
Conventional RF couplers are difficult to integrate into crowded PCB layouts due to their length and number of ports, leading to integration challenges.
Innovation Solution
A dyadic radial coupler with an input port, coaxial conductor, and impedance transformer on a PCB, utilizing annular conducting strips for efficient RF signal coupling between layers, allowing for 0 dB or frequency-selective coupling with minimal loss and reduced surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional parallel-line or planar transmission line couplers are used, then RF signal coupling between PCB layers is achieved, but the length and number of ports make integration into crowded PCB layouts difficult
Solution Approach 1:
The patent transitions from conventional planar transmission lines to a radial coupler configuration that extends in multiple dimensions, using vertical vias to connect different PCB layers. This dimensional change allows the coupler to achieve signal coupling while occupying less lateral PCB area, effectively resolving the contradiction between compact layout and coupling functionality.
Solution Approach 2:
The radial coupler design embeds the coupling structure within the existing PCB layer structure, with the coupler positioned at the interface between layers and using shared ground references. This nesting approach integrates the coupler into the PCB architecture without requiring separate dedicated space, reducing overall layout complexity.
2Area of stationary object
If conventional RF couplers are used, then signal coupling is achieved, but the length of transmission lines increases the surface area required on PCB
Solution Approach 1:
The radial coupler utilizes vertical dimensionality through vias to achieve signal coupling between layers, eliminating the need for long lateral transmission lines. By transitioning from horizontal signal paths to vertical inter-layer coupling, the design dramatically reduces the PCB surface area required while maintaining coupling effectiveness.
Solution Approach 2:
The radial coupler employs a circular or annular geometry for the signal path, replacing straight linear transmission lines with curved radial trajectories. This curvature allows the signal to couple between layers in a compact circular footprint rather than requiring extended linear paths, reducing overall PCB area consumption.
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
Enables efficient RF signal propagation with minimal loss and reduced space requirements, supporting antenna arrays and frequency-selective filtering on PCBs.
Implementation Method 1
coaxial coupling of an RF signal is achieved between the input port and the coupled port
Implementation Method 2
The dyadic radial coupler includes an input port comprising a transmission line on an input layer of a PCB, a coaxial conductor, an end of the conductor operatively connected to the transmission line
Implementation Method 3
an impedance transformer integrated within the transmission line of the input port
Implementation Method 4
The coupled port is disconnected from additional circuit elements to allow the RF signal to radiate into free space. The dyadic radial coupler can include a microstrip patch and at least one ground plane on a PCB layer, causing the coupler to act as an antenna for the RF signal
Data Source
AI summary
A two-port dyadic radial coupler for RF communications between PCB layers is disclosed. The coupler includes an input port, an impedance matching transformer, a coaxial conductor, and at least one coupled port. The input or coupled port has an at least partially annular conducting strip axially aligned with the coaxial conductor, causing radial coupling excitation by an RF signal to couple the signal between the input port and coupled port. The coupler is configured for coupling of RF signals within a select frequency range at 0 dB attenuation. In other embodiments, the coupler is configured for frequency-selective coupling to attenuate undesired frequencies. In various embodiments, the RF signal is parasitically coupled to a plurality of coupled ports on intermediate layers of the PCB. In additional embodiments, the coupled port may be left disconnected from additional circuit elements, causing the coupler to act as an antenna.