Millimeter Wave Switching Circuit Symmetrical Ground Via Holes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional millimeter waveband switching circuits face challenges in achieving high isolation and low insertion loss due to limitations in shunt structure design, leading to increased chip size and manufacturing costs, with existing solutions failing to adequately address the requirement for -30 dB isolation in the transmitting/receiving path.
Innovation Solution
A switching circuit design featuring a symmetrical structure with vertically coupled transistors and multiple ground via holes, optimized capacitors, and bias pads to enhance OFF-state isolation while maintaining low ON-state insertion loss, utilizing a single-pole-double-throw (SPDT) switch configuration and field effect transistors to match the interested frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shunt structure is used in millimeter waveband switching circuits, then the circuit can block signal flow to output port, but the isolation is insufficient (cannot achieve -30 dB or less) and insertion loss increases
Solution Approach 1:
The switching circuit is divided into multiple stages, with each stage containing a switch element and ground via holes. This segmentation allows progressive signal blocking across stages, achieving high isolation while maintaining low insertion loss through the distributed structure
Solution Approach 2:
The patent transitions from a planar layout to a three-dimensional structure by utilizing vertical via holes that connect different layers. This dimensional change enables ground connections to be made directly beneath the transmission line, significantly improving isolation without increasing the footprint area
2Reliability
If multi-stage shunt technology is used to ensure high isolation, then isolation performance improves, but chip size and manufacturing cost increase due to additional inductors, capacitors, and transmission lines
Solution Approach 1:
The patent merges the functions of separate inductors and capacitors into integrated transmission line structures and via hole configurations. The transmission line itself provides the necessary impedance transformation and signal blocking, eliminating the need for discrete reactive components and reducing overall circuit complexity
Solution Approach 2:
The transmission line serves multiple functions simultaneously: it provides signal transmission, impedance transformation, and signal blocking through its interaction with ground via holes. This multi-functionality reduces the number of dedicated components needed, simplifying the overall circuit design
3Reliability
If transmission line and via hole are disposed vertically to minimize distance, then isolation improves per unit cell, but insertion loss increases due to increased transmission line impedance
Solution Approach 1:
The via holes are strategically positioned at specific locations along the transmission line where they provide maximum isolation benefit with minimum impact on impedance. This localized optimization ensures that ground connections are made at points that effectively block signals without creating excessive impedance variations that would increase insertion loss
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 proposed design achieves high isolation of 30 dB or more and low insertion loss across a 10 GHz bandwidth, reducing chip size and manufacturing costs by simplifying the circuit layout and eliminating the need for multi-stage shunt structures, while maintaining efficient signal transmission.
Implementation Method 1
Field effect transistors (FETs) such as a high electron mobility transistor (HEMT) or a metal-semiconductor field effect transistor (MESFET) has been widely used as a core element in the switching circuit
Implementation Method 2
The shunt structure functions to block a flow into an output port by coupling a ground via hole to a drain electrode or a source electrode of the switch element
Data Source
AI summary
Provided is a switching circuit for a millimeter waveband control circuit. The switching circuit for a millimeter waveband control circuit includes a switching cell disposed on a signal port path to match an interested frequency and including at least one transistor coupled vertically to an input/output transmission line and a plurality of ground via holes disposed symmetrically in an upper portion and a lower portion of the input/output transmission line; capacitors for stabilizing a bias of the switching cell; and bias pads coupled in parallel to the capacitor to control the switching cell. Therefore, the switching circuit may be useful to improve its isolation by simplifying its design and layout through the use of symmetrical structure of optimized switching cells without the separate use of different switch elements, and also to reduce its manufacturing cost through the improved yield of the manufacturing process and the enhanced integration since it is possible to reduce a chip size of an integrated circuit in addition to its low insertion loss.