A REVIEW OF COMPACT SUBSTRATE

INTEGRATED WAVEGUIDE (SIW)

INTERCONNECTS AND COMPONENTS
Maurizio Bozzi, Luca Perregrini, Cristiano Tomassoni

maurizio.bozzi@unipv.it
http://microwave.unipv.it/bozzi/
Maurizio Bozzi – SPI 2019
OUTLINE

1 – Current Trends in Microwave Technology (towards 5G)

2 – Substrate Integrated Waveguide (SIW) Technology

3 – Broadband and Miniaturized SIW Interconnects

4 – Miniaturization of SIW Components

5 – New Materials (3D-Printed materials, Textile, Paper)

Maurizio Bozzi – SPI 2019

1 – CURRENT TRENDS IN
MICROWAVE TECHNOLOGY
(TOWARDS 5G)

Maurizio Bozzi – SPI 2019

TRADITIONAL MICROWAVE TECHNOLOGIES

METALLIC WAVEGUIDES

PRINTED CIRCUIT BOARDS

DIELECTRIC RESONATORS,
ABSORBERS, RADOMES Maurizio Bozzi – SPI 2019
INTERNET OF THINGS (IOT)

IT/Networks

Security/Public safety

Industrial processes

Healthcare

Smart home

Energy management

Maurizio Bozzi – SPI 2019

INTERNET OF THINGS (IOT) & 5G

IT/Networks

Security/Public safety

5G Industrial processes

Healthcare

Smart home

Energy management

Maurizio Bozzi – SPI 2019

CAN WE STILL USE THESE TECHNOLOGIES?

Traditional microwave technologies are not suitable for the many

emerging applications. A new paradigm is needed!

Maurizio Bozzi – SPI 2019

TECHNOLOGICAL REQUIREMENTS
The key points for the development of Internet of Things/5G are:

low cost easy integration of the

complete wireless system

mm-wave frequency
self-powering
simple
(energy harvesting)
design rules
wearable devices

This leads to the selection of:

 An integration technology able to efficiently combine active
elements, passive components, and antennas;
 Suitable materials for each application.
Maurizio Bozzi – SPI 2019
2 – SUBSTRATE INTEGRATED
WAVEGUIDE TECHNOLOGY

Maurizio Bozzi – SPI 2019

TRADITIONAL TRANSMISSION LINES
The guided wave propagation in the microwave region is preferably
obtained by using microstrip lines and metallic waveguides.

MICROSTRIP LINES (planar) TECHNOLOGICAL GAP METALLIC WAVEGUIDES (non-planar)

 Light and compact  Low losses

 Low fabrication cost  Completely shielded
 High losses  Bulky and expensive
 High cross-talk  Difficulties with active components
Maurizio Bozzi – SPI 2019
SUBSTRATE INTEGRATED WAVEGUIDE
Substrate Integrated Waveguides (SIW) are novel transmission lines
that implement rectangular waveguides in planar form.

SIW consist of two rows of conducting cylinders embedded in a

dielectric substrate that connect two parallel metal plates.
Maurizio Bozzi – SPI 2019
 SIW COMPONENTS

SIW diplexer at 26 GHz

SIW circulator at 24 GHz

SIW post filter at 27 GHz

12 GHz SIW
oscillators

SIW dual-mode X-Band SIW amplifier

filter at 24 GHz X-band SIW mixer Maurizio Bozzi – SPI 2019
SYSTEMS-ON-SUBSTRATE (SOS)
Complete system integration by using one single technology!

Z. Li and K. Wu, “24-GHz Frequency-Modulation Continuous-Wave Radar Front-End System-on-

Substrate,” IEEE Trans. on Microwave Theory and Techniques, Vol. 56, No. 2, pp. 278-285, Feb. 2008.
Maurizio Bozzi – SPI 2019
3 – BROADBAND AND MINIATURIZED
SIW INTERCONNECTS

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SIW INTERCONNECTS
In classical SIW structures, the single-mode bandwidth is limited to
one octave and the width cannot be miniaturized, except for the
effect of the dielectric permittivity.
1600
full-wave simulation
1400

propagation constant [rad/m]

equivalent waveguide
1200 measurement

1000

800
f1 f2
600
w 400

200

0
10 20 30 40 50
frequency [GHz]

In some cases, wireless systems may require

broader bandwidth and smaller dimensions
Maurizio Bozzi – SPI 2019
MINIATURIZED/BROADBAND SIW
FOLDED SIW HALF-MODE SIW
metal via top metal layer virtual magnetic wall top metal layer
metal via metal via

metal septum
dielectric substrate bottom metal layer dielectric substrate
bottom metal layer
N. Grigoropoulos et al., IEEE Microwave W. Hong et al., 31th International Conference
Wireless Comp. Letters, 2005. on Infrared Millimeter Waves, 2006.

SLAB SIW RIDGE SIW

metal via top metal layer metal via ridge post top metal layer
metal via metal via

air holes metal strip

dielectric substrate dielectric substrate
bottom metal layer bottom metal layer

M. Bozzi et al., Intern. Journal RF & Microwave M. Bozzi et al., IET Microwave Antennas and
Computer–Aided Engineering, 2005. Propagation, 2010.
Maurizio Bozzi – SPI 2019
RIDGE SIW
The ridge SIW is based on a row of partial height metal cylinders
located in the broad side of an SIW and connected at their bottom with
a metal strip.

M. Bozzi, S.A. Winkler, and K. Wu, “Broadband and Compact Ridge Substrate Integrated
Waveguides,” IET Microwave Antennas and Propagation, Vol. 4, No. 11, pp. 1965–1973, Nov. 2010.

Maurizio Bozzi – SPI 2019

 RIDGE SIW
A ridge SIW covering the frequency band
6.8–25.0 GHz was designed and fabricated
(with 168% bandwidth enhancement).

2000

mono-modal band
1600
propagation constant [rad/m]

1200

800
f1=6.8 GHz f2=25.0 GHz

400 1st mode

2nd mode
measurement
0
0 5 10 15 20 25 30
frequency [GHz]
Maurizio Bozzi – SPI 2019
RIDGE SISW

The bandwidth can be further improved by adding air holes in the

lateral side of the ridge SIW, thus implementing a ridge substrate
integrated slab waveguide (SISW).

Maurizio Bozzi – SPI 2019

RIDGE SISW

A ridge SISW covering the frequency band

7.1–30.7 GHz was designed and fabricated
(with 232% bandwidth enhancement).

2000

mono-modal band
1600
propagation constant [rad/m]

1200

800
f1=7.1 GHz f2=30.7 GHz

400 1st mode

2nd mode
measurement
0
5 10 15 20 25 30 35
frequency [GHz]
Maurizio Bozzi – SPI 2019
 TWO-MATERIAL RIDGE SIW
The ridge SIW based on two different substrate materials has been
proposed to increase the single-mode bandwidth of the classical SIW.

FUNDAMENTAL (TE10) MODE SECOND (TE20) MODE

S. Moscato, R. Moro, M. Pasian, M. Bozzi, and L. Perregrini, "Two-Material Ridge Substrate Integrated
Waveguide for Ultra-Wide Band Applications," IEEE Transactions on Microwave Theory and Techniques,
Vol. 63, No. 10, pp. 3175-3182, Oct. 2015. Maurizio Bozzi – SPI 2019
TWO-MATERIAL RIDGE SIW
Top layer: Taconic TLY-5, thickness 1.52 mm, permittivity 2.2
Bottom layer: Taconic CER-10, thickness 0.64 mm, permittivity 9.5

-5 |S11| simulation
|S11| measurement
|S21| simulation

S-parameters (dB)
-10
|S21| measurement

-15

-20

-25

-30
2 4 6 8 10 12 14
Frequency (GHz) Maurizio Bozzi – SPI 2019
TWO-MATERIAL RIDGE SIW
Measurement of the second mode

Single mode bandwidth

almost 10 GHz (2.5-12 GHz)
Maurizio Bozzi – SPI 2019
4 – MINIATURIZATION
OF SIW COMPONENTS

Maurizio Bozzi – SPI 2019

FOLDED SIW FILTER
This filter is based on a folded SIW
dual-mode cavity, with insets in the
central metal septum.
The size of the filter is 0.45λ0×0.24λ0.

R. Moro, S. Moscato, M. Bozzi, L. Perregrini, "Substrate Integrated Folded Waveguide Filter with Out-
of-Band Rejection Controlled by Resonant-Mode Suppression," IEEE Microwave Wireless Comp.
Letters, Vol. 25, No. 4, pp. 214-216, April 2015. Maurizio Bozzi – SPI 2019
HALF-MODE SIW FILTER
The same filter can be implemented in
half-mode SIW, based on a single-
layer technology.
The size of the filter is 0.42λ0×0.20λ0.

N. Delmonte, L. Silvestri, M. Bozzi, and L. Perregrini, "Compact Half-Mode SIW Cavity Filters Designed
by Exploiting Resonant Mode Control," International Journal of RF and Microwave Computer-Aided
Engineering, Vol. 26, No. 1, pp. 72–79, Jan. 2016. Maurizio Bozzi – SPI 2019
QUARTER-MODE SIW FILTERS
Quarter-mode cavities allow a size
reduction of a factor 4 and selection
of the resonant modes.

S. Moscato, C. Tomassoni, M. Bozzi, and L. Perregrini, "Quarter-Mode Cavity Filters in Substrate

Integrated Waveguide Technology," IEEE Transactions on Microwave Theory and Techniques, Vol. 64,
No. 8, pp. 2538-2547, Aug. 2016. Maurizio Bozzi – SPI 2019
QUARTER-MODE SIW FILTERS
Size reduction of a factor 4 and selection of the resonant modes.

3 4
2-pole filter

4-pole filter
2
1 1 2

-5

S-parameters (dB)
-10

-15

-20
|S11| simulation
-25 |S11| measurement
|S21| simulation
|S21| measurement
-30
2 3 4 5 6 7 8 9
Frequency (GHz)

Maurizio Bozzi – SPI 2019

AIR-FILLED SIW FILTERS
Partially air-filled SIW cavities can be exploited to design band-pass filters
with transmission zeros. The relative frequency separation can be
controlled by changing the size a of the air filled portion.
Homogeneous cavity Partially air-filled cavity

C. Tomassoni, L. Silvestri, A. Ghiotto, M. Bozzi, and L. Perregrini, "Substrate Integrated Waveguide

Filters Based on Dual-Mode Air-Filled Resonant Cavities," IEEE Transactions on Microwave Theory and
Techniques, Vol. 66, No. 2, pp. 726-736, Feb. 2018. Maurizio Bozzi – SPI 2019
 AIR-FILLED SIW FILTERS
Narrow-band filter
Broad-band filter

Maurizio Bozzi – SPI 2019

AIR-FILLED SIW FILTERS

Maurizio Bozzi – SPI 2019

 5 – NEW MATERIALS:
3D-PRINTING, TEXTILE, PAPER

Maurizio Bozzi – SPI 2019

 3D-PRINTED SLAB SIW
A substrate integrated slab waveguide (SISW) was implemented by FDM
by using ABS filament, by modifying the permittivity in the side portions.

Standard 3D-printed SIW 3D-printed slab SIW

50% bandwidth
enhancement.

E. Massoni, L. Silvestri, G. Alaimo, S. Marconi, M. Bozzi, L. Perregrini, and F. Auricchio, “3D-Printed

Substrate Integrated Slab Waveguide for Single-Mode Bandwidth Enhancement,” IEEE Microwave and
Wireless Components Letters, 2017. Maurizio Bozzi – SPI 2019
 TEXTILE COMPONENTS & ANTENNAS

-10

-20

S-parameters [dB]
-30

-40

INTERCONNECT FOLDED FILTER

-50

-60
S11 Simulated
S11 Measured

-70 S21 Simulated

S21 Measured
-80
1 2 3 4 5 6 7 8 9
frequency [GHz]

R. Moro, S. Agneessens, H. Rogier, M. Bozzi,

“Wearable Textile Antenna in Substrate Integrated
Waveguide Technology,” Electronics Letters, 2012

2014 Premium Award for Best Paper

in Electronics Letters CAVITY-BACKED ANTENNA
Maurizio Bozzi – SPI 2019
INK-JET PRINTING ON PAPER SUBSTRATES
Collaboration with
GATech, Atlanta

SLOTTED WAVEGUIDE ANTENNA

S. Kim, B. Cook, T. Le, J. Cooper, H. Lee, V. Lakafosis, R.

INTERCONNECTS Vyas, R. Moro, M. Bozzi, A. Georgiadis, A. Collado, and M.
Tentzeris, "Inkjet-printed Antennas, Sensors and Circuits on
Paper Substrate," IET Microwaves, Antennas and Propagation,
Vol. 7, No. 10, pp. 858–868, July 16, 2013.

2015 Premium Award for Best Paper

in IET Microwave Antennas & Propagation

CAVITY FILTER Maurizio Bozzi – SPI 2019

 MILLING OF PAPER SUBSTRATES

HALF-MODE SIW

-10
S-parameters (dB)

-20

-30

-40

HALF-MODE -50
|S11| simulation
|S11| measurement

SIW FILTER -60

|S21| simulation
|S21| measurement

2 4 6 8
Frequency (GHz)
10 12 14 QUARTER-MODE SIW FILTER

S. Moscato, R. Moro, M. Pasian, M. Bozzi, and L. Perregrini, “An Innovative Manufacturing Approach for
Paper-based Substrate Integrated Waveguide Components and Antennas,” IET Microwaves, Antennas and
Propagation, Vol. 10, No. 3, pp. 256–263, 19 Feb. 2016. Maurizio Bozzi – SPI 2019
CONCLUSION

 The next generation of wireless systems for application in the

Internet of Things and 5G will require a completely new approach
for the integration technology and material selection.

 Substrate Integrated Waveguide is an excellent candidate to

integrate complete systems at microwave and millimeter waves.

 The use of novel materials like paper, textile, and 3D-printed

materials has been demonstrated for the manufacturing of SIW
components and antennas.

Maurizio Bozzi – SPI 2019

 A REVIEW OF COMPACT SUBSTRATE
INTEGRATED WAVEGUIDE (SIW)
INTERCONNECTS AND COMPONENTS
Maurizio Bozzi, Luca Perregrini, Cristiano Tomassoni

maurizio.bozzi@unipv.it
http://microwave.unipv.it/bozzi/
Maurizio Bozzi – SPI 2019