“Magic Cube” Antennas
32 mm
32 mm
32 mm
feed point
•Thin LCP material for cube
•Low-cost: printed and then
folded into three-dimensional
shape
•Easily re-designable for any
chip input impedance to achieve
conjugate impedance matching
•Used for RFID and Wireless
Sensor Node (WSN) technology
•Omnidirectional Radiation
pattern
•Uses all six sides in antenna
design
Fabricated Antenna• Meander line structure on the
cube with inductive couple allows for miniaturization of the length of each side and conjugate matching
• Planar designs can be manipulated to have similar characteristics without a directionally-specific orientation
• In certain meander line structures, dual-band performance is achieved
-30
-25
-20
-15
-10
-5
0
0.8 0.84 0.88 0.92 0.96 1 1.04
freq (GHz)
S11 (
dB
)
Simulation
Meas 1 no styro
Meas 2 no styro
Meas 3 no styro
Meas 1 Styro
New Flexible Magnetic Composite
Material
• Magnetic composite – fabricated from 40 vol% BaCo ferrite powder in Dow Corning Sylgard 184
silicone
– produced with a mixer at 240 rpm and 110°C for 30 minutes
• 95% CI (Confidence Interval) for mean of εr , µr, , tanδe and tanδm basedon 5 measurements
• h (substrate thickness) = 1.3 mm
mean Lower CI Upper CI
εr 7.142 7.083 7.201
µr 2.463 2.457 2.468
tanδe 0.0017 0.0005 0.0028
tanδm 0.0391 0.0358 0.0424
RFID tag on magnetic composite
• Antenna designed for UHF RFID band = 480 MHz
• Miniaturization concept proven by comparing the resonant frequency of the pure silicone design vs. composite
• Silicone fres = 6 GHz
• Composite fres = 480 MHz
• Miniaturization factor = 1.25
• For structures with ground plane even further miniaturization
66mm
19.8m
m
6.8mm
7.2mm
-35
-30
-25
-20
-15
-10
-5
0
0.4 0.45 0.5 0.55 0.6 0.65 0.7
Frequency (GHz)
S1
1 (
dB
)
Magnetic Material
Silicone Substrate
Conformal performance
• Antenna bent for conformal performance analysis– Foam cylinder 54 mm in diameter
– Slight downshift in frequency of 6 MHz
• Medical monitoring and pharma applications
-20
-15
-10
-5
0
0.4 0.45 0.5 0.55 0.6
Frequency (GHz)
S1
1 (
dB
)
Flat
Cylinder Radius 54mm
