Waveguide Module Trench Absorber for Substrate Mode Suppression
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Solution Overview
Problem
As operating frequencies increase to the millimeter or sub-millimeter band, unnecessary modes, particularly substrate modes, are generated inside waveguides due to chip and surrounding structure arrangements, leading to deteriorated performance, insertion loss, and return loss, which existing methods struggle to effectively suppress.
Innovation Solution
A waveguide module structure incorporating a radio wave absorber or metal structure within trench structures on the side surfaces of the chip, reducing the space between the chip and waveguide, and using conductive adhesives or absorbing pastes to enhance absorption and suppress unnecessary modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vias for backside are densely disposed to suppress substrate mode, then substrate mode suppression is improved, but device complexity and manufacturing process complexity increase
Solution Approach 1:
The invention extracts the substrate mode suppression function from the chip structure itself and relocates it to the waveguide module structure by adding a radio wave absorber in the waveguide. This separates the suppression function from the chip manufacturing process, avoiding the need for complex via structures while achieving the same suppression effect.
Solution Approach 2:
The radio wave absorber acts as an intermediary element placed in the waveguide to suppress substrate modes. Instead of modifying the chip with complex via structures, the absorber mediates the interaction between the chip and waveguide environment to achieve mode suppression.
2Reliability
If space between chip and waveguide is reduced to suppress substrate mode, then substrate mode suppression is improved, but ease of manufacture deteriorates
Solution Approach 1:
The invention addresses the spacing issue by adding a vertical dimension element (radio wave absorber) in the waveguide rather than relying solely on reducing the horizontal gap between chip and waveguide. This dimensional approach allows maintaining easier chip attachment while achieving mode suppression.
3Speed
If operating frequency is increased to millimeter or sub-millimeter band, then transmission speed is improved, but unnecessary mode generation increases
Solution Approach 1:
The invention converts the harmful substrate modes generated at high frequencies into a beneficial situation by placing a radio wave absorber that specifically targets and absorbs these modes. The high-frequency operation that generates unwanted modes is countered by the absorber's frequency-selective absorption capability.
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 structure improves insertion loss and return loss by effectively suppressing unnecessary modes, enhances transmission characteristics, and reduces manufacturing complexity and cost by eliminating the need for additional semiconductor processes.
Implementation Method 1
a radio wave absorber disposed in the trench structure
Data Source
AI summary
Provided is a waveguide module for improving insertion loss and return loss. The waveguide module includes a metal jig including a waveguide through which a radio wave is transmitted and received formed therein, a chip disposed on the waveguide formed in the metal jig and including a plurality of circuits that is configured to transmit and receive radio waves inside the waveguide, and a circuit board configured to provide a bias used for an operation of the chip, wherein the metal jig includes a trench structure to dispose a radio wave absorber on a side surface of the chip in a direction crossing the waveguide.