Integrated Circulator for Phased Arrays Using Magnetic Substrate
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Solution Overview
Problem
Conventional circulators and isolators face challenges in phased array antennas and other RF devices due to space limitations, as they require a stronger magnetic field with increasing frequency, making it difficult to scale down and integrate these devices effectively within the limited space of phased array antennas.
Innovation Solution
A circulator/isolator assembly is designed with a first magnetic substrate and a dielectric layer having a multi-port junction circuit coupled to RF transmission traces, where a magnet excites a unidirectional magnetic flux field, allowing for compact integration by using a self-biasing ferrite material or multiple magnets for enhanced magnetic field strength without increasing physical size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circulators or isolators are used in phased array antennas, then electromagnetic wave propagation can be controlled in one direction, but the device size increases and space availability is reduced
Solution Approach 1:
The patent combines the circulator/isolator functionality with the antenna substrate by integrating the magnetic substrate directly onto the printed circuit board. This merging eliminates the need for separate discrete circulator components, thereby reducing the overall device footprint while maintaining the necessary electromagnetic wave propagation control functionality.
Solution Approach 2:
The patent transitions from a three-dimensional discrete component structure to a planar integrated structure by placing the magnetic substrate directly on the PCB surface. This dimensional change allows the circulator functionality to be achieved within the two-dimensional plane of the antenna substrate, significantly reducing the required space.
2Speed
If the operating frequency of the antenna is increased, then the wavelength decreases and element spacing is reduced, but the magnetic field strength requirement increases and device scaling becomes difficult
Solution Approach 1:
The patent addresses the frequency-scaling issue by changing the magnetic substrate parameters. Specifically, the magnetic substrate is designed with properties that allow it to maintain effective magnetic field strength across different operating frequencies without requiring proportionally stronger magnets, thereby enabling device scalability to higher frequencies.
Solution Approach 2:
The patent employs composite material structures where the magnetic substrate is integrated with the dielectric substrate. This composite approach allows optimization of magnetic properties independent of the electromagnetic substrate properties, enabling the device to scale to higher frequencies while maintaining compact dimensions.
3Force
If a stronger permanent magnet is used to meet higher operating frequency requirements, then the magnetic field strength is sufficient, but the device size and packaging complexity increase
Solution Approach 1:
The patent merges the magnetic substrate with the antenna PCB structure, eliminating the need for separate magnet housings and complex mounting arrangements. This integration simplifies the overall packaging while providing sufficient magnetic field strength for high-frequency operation.
Solution Approach 2:
The patent optimizes the magnetic substrate parameters to achieve the required magnetic field strength with a compact design. By carefully selecting and tuning the magnetic material properties and geometric configuration, sufficient field strength is achieved without requiring large or complex magnet assemblies.
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 efficient electromagnetic wave propagation in one direction, achieving near-zero insertion loss and isolation loss over a specific frequency range, while reducing the overall footprint of the antenna system by allowing the circulator/isolator to share a non-magnetic substrate with the printed circuit board.
Implementation Method 1
A circulator device uses the gyromagnetic properties of the ferrite material, typically yttrium-iron-garnet (YIG), for its low loss microwave characteristics. The ferrite substrate is biased by an external, static magnetic field from a permanent magnet. The magnetic lines of flux in the ferrite substrate propagate in only one circular direction, thus forming a non-reciprocal path for electromagnetic waves to propagate
Data Source
AI summary
A circulator/isolator assembly is disclosed. The assembly includes a first magnetic substrate having first surface and a second surface and a first ground plane formed on the first surface. A dielectric layer is disposed adjacent first magnetic substrate. The dielectric layer includes a multi-port junction circuit coupled to transmission traces. One of the traces forms an input port and another forms an output port. A first magnet is disposed proximate the multi-port junction circuit of the dielectric layer. The first magnet excites a circular, unidirectional magnetic flux field in the first magnetic substrate that limits electromagnetic wave propagation to a single direction.