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Cross section of the Split Post Dielectric Resonator (SPDR)
Split post dielectric resonators (SPDR)
SPDRs are intended for the measurements of the complex
permittivity of laminar dielectric materials including LTCC
substrates, but also thin ferroelectric films deposited on low
loss dielectric substrates. Additionally, SPDRs can be used
for the measurements of the surface resistance and
conductivity of various conducting materials such as
commercial resistive layers, thin conductive polymer films or
high resistivity semiconductors. Such measurements are only
possible for large surface resistance samples with Rs > 5
Accuracy of measurements of a sample of thickness h Δε/ε=±(0.0015 + Δh/h)

Δtanδ=±2*10-5 or ±0.03*tanδ whichever is higher
Operational frequency range SPDR uses a particular resonant mode. This mode has a particular resonant frequency depending on resonator's dimensions but also, to some extent, on the electrical properties of the measured sample. Thus, each resonator is designed for a particular nominal frequency and the actual measurement is taken at a frequency close to the nominal one. The nominal frequencies of the basic line of SPDRs are: 1.1 GHz, 1.9 GHz, 2.45 GHz, 5 GHz, 10 GHz. Resonators for the other frequencies in the range between 1.1 and 15 GHz can be manufactured upon special request.
Operational temperature range -2700C ÷ 1100C
Additional equipment needed to perform measurement Microwave Q-Meter or
Vector Network Analyser
Measurement procedure
Resonant frequency and Q - factor of the empty resonator and
the resonator with investigated sample are measured.
Dedicated software is provided for permittivity and dielectric
loss tangent determination. The users who have access to one
of the PNA/ENA Series network analysers by Agilent
Technologies equipped with 85071E Material Measurement
software with Option 300 simply upload the QWED's
dedicated application into the network analyser and obtain the
final results directly on its display.
The users working with different network analysers need to
install the software for dielectric properties calculation on a
standard PC computer or network analyser if equipped with
Windows® operating system.
Additional information Minimum size of a sample depends on the operating frequency of the resonator. The minimum sizes of samples for the most popular operating frequencies of the resonators are shown in Table 1a.
Table1: Parameters of Split Post Dielectric Resonators (SPDR)
Table1a: The minimum sizes of sample according to operating frequencies
Nominal frequency [GHz] Minimum sizes of sample [mm] Maximum thickness of sample [mm]
1.1 120x120 6.0
1.9 70x70 4.0
3.2 50x50 3.0
5 ÷ 6 30x30 2.0
9 ÷ 10 22x22 1.0
13 ÷ 15 15x15 0.6
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