Substrate Integrated Waveguide

The English term Substrate Integrated Waveguide (SIW), for which there is currently no German translation used by the majority, describes a new electrical line. This new form of waveguide was first presented in 1998 by the Japanese scientist Hiroshi Uchimura and others.

The line, which is designed as a waveguide , consists solely of a dielectric that is conductively coated on both sides , also called a substrate, and electrical plated-through holes , so-called vias, as a boundary. Advantages of this technology compared to conventional waveguides are the simple production, the flat profile and the possibility of applying additional components to the same substrate.

properties

The main properties of the SIW are comparable to those of the rectangular waveguide. There are adequately empirically obtained approximation formulas that link the width of an SIW with the width of a rectangular waveguide. The limit frequencies must also be determined based on the dimensions of the SIW . A special feature of the SIW is that the cut-off frequency does not depend on the substrate thickness, but solely on the width.

The equivalent width of a waveguide, which has roughly the same properties as the corresponding SIW, is approximately linked using the following formula:

${\displaystyle a_{\text{RWG}}=a_{\text{SIW}}-1{,}08\cdot {\frac {(2r)^{2}}{p}}+{\frac {(2r)^{2}}{10\cdot a_{\text{SIW}}}}}$

where is the distance between the delimiting vias and the radius of the vias used, as well as and the respective widths of the waveguide or SIWs. ${\displaystyle p}$ ${\displaystyle r}$ ${\displaystyle a_{\text{RWG}}}$ ${\displaystyle a_{\text{SIW}}}$

In the SIW, only field types are capable of spreading, since the wall currents in the short side walls can only have one vertical component. ${\displaystyle H_{m0}}$

Applications

Applications of the SIW are antennas , feed lines of antennas (engl. Feeding ), couplers , etc. a., especially in the millimeter band , i.e. beyond 30 GHz. Flexible transitions to other technologies already exist, such as microstrip lines , coplanar waveguides (CPW), waveguides or coaxial cables .

literature

• Xuan Hui Wu, Ahmed Kishk: Analysis and Design of Substrate Integrated Waveguide Using Efficient 2D Method . Morgan & Claypool Publishers, 2010, ISBN 978-1-59829-902-1 .

Web links

• Presentation of the SIW on the English site Microwave 101 (English)
• Design of Substrate Integrated Waveguide Components (accessed November 16, 2017)
• A Review on Substrate Integrated Waveguide and its Microstrip Interconnect (accessed November 16, 2017)
• High performance multilayer Substrate Integrated Waveguide (SIW) technics for low-cost millimeter-wave circuits (accessed on November 16, 2017)
• Substrate Integrated Waveguide Antenna Applications (accessed November 16, 2017)