Selected Applications of Tunable Materials for Microwave Components Matthias Maasch, Onur Hamza Karabey, Sebastian Strunck and Rolf Jakoby Mircowave Engineering, Technische Universität Darmstadt
Selected Applications of Tunable Materials for Microwave Components
Matthias Maasch, Onur Hamza Karabey, Sebastian Strunck and Rolf Jakoby
Mircowave Engineering, Technische Universität Darmstadt
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Tunable Materials for Microwave Components
Phase shifter in antenna arrays for beam forming
Matching networks
Power amplifiers
Implementation of tunability by using
Liquid Crystal above 10GHz
Ferroelectrics (Barium-Strontium-Titanate) below 15GHz
Metamaterials
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Outline
Coaxial Transmission Line for Liquid Crystal Charaterization
Thermal Effects in Interdigital Capacitors
Tunable SRR loaded Waveguide
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Coaxial Transmission Line for Liquid Crystal Charaterization
Thermal Effects in Interdigital Capacitors
Tunable SRR loaded Waveguide
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LC Characterization Setup
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LC Characterization Setup
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10 20 30 40 50-5
-4
-3
-2
-1
0
f (GHz)
|S2
1|/d
B
no EM leakage
incl. EM leakage
EM Leakage through Filling Channels
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Simulated Impact of Filling Channels
Karabey et al. “Precise Broadband Microwave Material Characterization of Liquids” EuMW 2010
Error due to EM leakage: r’ : <6% r’’ : <40%
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Coaxial Transmission Line for Liquid Crystal Charaterization
Thermal Effects in Interdigital Capacitors
Tunable SRR loaded Waveguide
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Interdigital Capacitor on BST
r of BST is tunable by static E-field
Cheap printing technology
Better linearity compared to semiconductor varactors
High power capability ‟ thermal effects?
Alumina (250µm)
BST (10µm)
Gold (3µm)
Gold (3µm)
+VDC
-VDC
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Simulated Temperature
IDC size: 200x600µm2
Gap width: 20µm
Finger width: 20µm
BST RF properties
r = 200, tan = 0.02
RF input power:50W @ 2GHz
Maximum temperature ≈ 52°C
Temperature inside BST layer ≈ 37°C
He “Heat capacity, thermal conductivity, and thermal expansion of barium titanate-based ceramics” Thermochimica Acta, 2004
BST
Alumina
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Coaxial Transmission Line for Liquid Crystal Charaterization
Thermal Effects in Interdigital Capacitors
Tunable SRR loaded Waveguide
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Tunable SRR loaded Waveguide
Maasch et al. “Voltage Tunable Split-Ring-Resonators for Waveguide Applications” Metamaterials 2009
Introduction of tunability to Split Ring Resonators by loading the gap
Phase shifter, filter inside a waveguide
Step towards voltage tunable 3D Metamaterial
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DC-Biasing of SRR Array
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Simulated Impact of Bias Elements
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Simulation of Tuning
theoretical tuning range: 0.7…2.4GHz
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Measurement Setup
9 SRRs with 9x9mm2
Substrate: RT/duroid 5880, t=0.38mm
Biasing Resistor
Varactor Diode
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Measurement Results
measured tuning range: 0.9…2.2GHz
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Thank you for your attention.