Vertical PIN Diode Transmission Line for Compact Millimeter-Wave Layouts
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Solution Overview
Problem
Existing millimeter wave transmission lines using surface mount diodes are limited by large size and design constraints, particularly when stacked substrates are used, restricting the freedom in antenna and circuit design and requiring additional power circuitry.
Innovation Solution
A vertical type PIN diode is implemented within a substrate using semiconductor process technology, forming a transmission line with a diode layer, upper and lower signal application substrates, and bonding films, allowing for adjustable response characteristics through diameter and thickness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If SMD type diode is used in millimeter wave transmission line, then the diode can be mounted on flat substrate, but the size becomes large and design freedom is limited
Solution Approach 1:
The patent transitions from horizontal mounting of SMD diodes on flat substrates to vertical mounting of PIN diodes through stacked substrates. The diode is positioned vertically between upper and lower substrates, utilizing the third dimension (height) to reduce the footprint area while maintaining electrical functionality. This dimensional change allows compact integration without sacrificing mounting capability.
Solution Approach 2:
The PIN diode is embedded within the stacked substrate structure, nesting the diode between the upper and lower substrates. The metal columns extend through the substrates to connect with the diode, creating a compact nested arrangement where the diode is integrated within the substrate assembly rather than mounted on the surface, thereby reducing overall size.
2Ease of manufacture
If SMD type diode is used on flat substrate, then mounting is possible, but additional power circuit is needed and design freedom is restricted
Solution Approach 1:
The patent combines the signal transmission function and power application function into a single stacked substrate structure. The upper substrate applies both the millimeter wave signal and the bias voltage to the PIN diode through integrated metal columns and bonding films. This merging eliminates the need for separate power application circuits that would be required for SMD diodes on flat substrates, thereby reducing device complexity.
Solution Approach 2:
The stacked substrate structure serves multiple functions simultaneously: it provides mechanical support, transmits the millimeter wave signal, applies bias voltage, and enables vertical diode mounting. The metal columns and bonding films are designed to handle both RF signal transmission and DC power delivery, making the structure universal and eliminating the need for additional dedicated power circuits.
3Ease of manufacture
If stacked type substrate is used with SMD diode, then mounting is possible, but degree of freedom in antenna and circuit design is greatly limited
Solution Approach 1:
By moving to vertical mounting in the stacked substrate configuration, the patent frees up horizontal space on the substrate surfaces. This allows greater flexibility in designing antenna patterns and circuit layouts on the upper and lower substrates, as the diode no longer occupies significant horizontal area or requires specific flat-substrate mounting configurations. The vertical orientation provides adaptability in spatial arrangement.
Solution Approach 2:
The stacked substrate structure divides the system into distinct upper and lower substrate layers with the diode positioned vertically between them. This segmentation allows independent optimization of antenna and circuit designs on each substrate without being constrained by the mounting requirements of a horizontally-mounted diode. Each substrate can be designed with greater freedom for its specific function.
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 vertical PIN diode enables miniaturization and flexible design, improving design freedom for antennas and circuits while providing different responses based on applied voltage, outperforming traditional SMD type diodes in size and functionality.
Implementation Method 1
when a reverse voltage is applied to the diode, the diode operates as a capacitor rather than an open circuit to transfer the millimeter wave signal
Implementation Method 2
the vertical type PIN diode may be configured with a P-type doped region adjacent to the upper bonding film, an N-type doped region adjacent to the lower bonding film, and a true semiconductor region located between the P-type and N-type doped regions
Data Source
AI summary
This transmission line for a millimeter wave band using a vertical type PIN diode comprises: a diode layer comprising a vertical type PIN diode and a metal column of the same size as the vertical type PIN diode; an upper signal application substrate which is located on the diode layer and comprises metal columns for transferring a millimeter wave signal to the diode layer; a lower signal application substrate located under the diode layer; an upper bonding film for connecting the diode layer to the upper signal application substrate; and a lower bonding film for connecting the diode layer to the upper signal application substrate. By applying a vertical type PIN diode which is very small in size compared to SMD type diodes of existing types and may be mounted within an intermediate substrate, the freedom in designing an antenna and a circuit may be significantly improved.