US 12166262 B1Patent grantUnited States

Broadband Millimeter-Wave Waveguide Transition

Official patent title

Apparatus, methods and design system for wide-band millimeter wave RWG to air-filled SIW transition

Arabic title: جهاز وطرق ونظام تصميم لانتقال واسع النطاق للموجات المليمترية من RWG إلى SIW مملوء بالهواء

Invention

Problem

Rectangular waveguides offer strong millimeter-wave performance but can be costly and difficult to integrate with planar substrate-integrated waveguides. Existing transitions may require design-specific optimization and can neglect higher-order mode purity, particularly for air-filled SIW.

Why it matters

Reliable wideband interconnection between RWG and SIW or AFSIW is important for compact millimeter-wave communication, radar, sensing, and imaging hardware. A systematic design method can shorten development and reduce reliance on repeated numerical optimization.

Approach

The technology uses tapered hollow metallic transitions between RWG and SIW or AFSIW interfaces and an analytical design process that calculates transition length, impedance matching, reflection, and modal behavior. The structures can be fabricated by CNC micromachining for operation across approximately 50–75 GHz.

Who may benefit

Potential beneficiaries include millimeter-wave component manufacturers, 5G and WiGig radio developers, radar and sensor designers, microwave test-equipment companies, and PCB/SIW integration teams.

Potential value

A single analytical framework addresses both dielectric-filled SIW and air-filled AFSIW transitions, with claimed dimensional ranges and documented reflection, modal-purity, insertion-loss, and bandwidth results across four design examples.

Background

Millimeter-wave systems are used in high-speed communications, radar, sensing, imaging, inspection, and wireless-power research. Rectangular metal waveguides handle power well but can be structurally complex and expensive to integrate. SIW offers planar integration, while AFSIW removes dielectric material to reduce insertion loss and improve power handling. Both still need a transition to external RWG feeds. The patent addresses this interface with a tapered structure and a theory-based design process intended to manage impedance, reflection, and mode conversion without a separate optimization workflow for each SIW technology.

Technology overview

Each transition is a hollow metallic taper whose RWG-side and SIW/AFSIW-side apertures are dimensioned for impedance matching. The design system uses waveguide dimensions, resonant frequency, effective dielectric constant, and propagation parameters to calculate a short transition length and total reflection. Claims cover 1–15 mm transitions, aperture heights around 0.2–1.0 mm, specified VSWR and modal-purity ranges, and 50–75 GHz operation. The description reports four validation examples, insertion loss as low as 0.35 dB, and 40% relative bandwidth.

Potential applications

Waveguide interconnects for 5G, WiGig, and other millimeter-wave radios.
Automotive, industrial, and imaging radar front ends.
Millimeter-wave sensors, security screening, and nondestructive evaluation.
RWG-to-SIW interfaces for compact PCB-integrated modules.
Laboratory and production-quality-monitoring microwave systems.

Evidence-supported advantages

Uses one systematic design approach for both SIW and AFSIW transitions.
Addresses impedance matching, reflection, and modal purity analytically.
Supports a claimed wide operating range of approximately 50–75 GHz.
Reports insertion loss as low as 0.35 dB and 40% relative bandwidth in design examples.
Defines compact tapered structures compatible with CNC micromachining.

Development stage

Analytical design and four validation examples are described; physical hardware validation and commercialization were not independently established.

Commercial opportunity

The design may support component licensing, design-software integration, or joint development with mmWave module, radar, and test-equipment manufacturers. Commercial adoption would require hardware prototypes, tolerance analysis, connector and packaging integration, repeatable high-frequency measurements, and manufacturability assessment. Cost and repeatability across frequency bands would guide adoption.

Patent classifications

WIPO IPC

H01P5/08Waveguides; resonators, lines or other devices of the waveguide type
H01P1/208Waveguides; resonators, lines or other devices of the waveguide type

CPC

H01P5/082Waveguides; resonators, lines or other devices of the waveguide type
H01P1/2088Waveguides; resonators, lines or other devices of the waveguide type
H01P5/024Waveguides; resonators, lines or other devices of the waveguide type

Inventors

First inventorMuhammad Shah Alam
InventorAsif Alam
InventorKhalid Almuhanna

Keywords

millimeter wave
rectangular waveguide
SIW
AFSIW
wideband transition
impedance matching
modal purity
CNC micromachining
5G
radar

Patent document and drawings

The patent publication is mapped to this record. Patent drawings remain within that publication; no separately cleared public media package has been supplied.