IEC 61338-1-3:1999 pdf download

IEC 61338-1-3:1999 pdf download.Waveguide type dielectric resonators – Part 1-3: General information and test conditions – Measurement method of complex relative permittivity for dielectric resonator materials at microwave frequency
1 Scope and object
This part of IEC 61 338 describes the dielectric rod resonator measurement method for a wide range of microwave dielectric properties in practical applications. This method has the following characteristics:a complete and exact mathematical solution of complex relative permittivity is given by easy computer software; the measurement error is less than 0,3 % for å 2 and less than 0,05 × 10 –4 for tan ä ; the TCF is directly measured without any compensation with a measurement error less than 1 × 1 0 –6 /K. The object of this standard is to describe the measurement methods of the complex relative permittivity of dielectric resonator materials at microwave frequencies by means of the dielectric rod resonator method short-circuited at both ends by parallel conducting plates. The measuring parameters are å 2, tan ä , TCF and the temperature dependence of tan ä at the resonance frequency. The dielectric materials are assumed to be isotropic and homogeneous.
3 3.1 Theory and calculation equations
Relative permittivity and loss factor
Figure 1 shows the configuration of the TE 0m mode resonator. A cylindrical dielectric rod is short-circuited at both ends by the two parallel conducting plates, thus constituting a resonator. The values å 2 and tan ä of this resonator are calculated from the measured resonance frequency ( f 0 ) and unloaded quality factor ( Q u ) of the TE 0m TE 01 1 , TE 01 2 and TE 01 3 modes are commonly used.
In the case of measurement of temperature properties, the apparatus is fixed in a temperature-controlled oven. For the measurement of dielectric properties, only the information on the amplitude of transmitted power is needed, that is, the information on the phase of the transmitted power is not required.
5.2 Measurement apparatus for complex permittivity
Figure 7 shows a measurement apparatus of the complex permittivity of a dielectric resonator. The apparatus is made of two flat conducting plates and two semi-rigid cables. The upper conducting plate can be moved up and down so that it can be adjusted to the height of the dielectric specimen. In order to minimize the measurement error, the two conducting plates must be parallel to each other and the diameter should be about three times larger than that of the dielectric specimen ( d 2 > 3 d in figure 1 ). Table 3 shows an example of the recommended dimensions and materials for the conducting plates. It is preferable that the conducting plates have a high conductivity. Therefore, metals such as silver, copper, and other metals plated by silver with a thickness greater than 5 µm, are often used. The surface of the plates shall be polished to a mirror-like sheen. The surface roughness should preferably be reduced to the order of 0,1 µm because the skin depth of the standard annealed copper is 0,66 µm at 1 0 GHz.
Each of the two semi-rigid cables has a small loop at the top so that the plane of the loop parallels that of the conducting plates. These cables can move right and left to adjust the insertion attenuation ( IA 0 ) to around 30 dB (figure 7). The IA 0 value shall be selected so as to be greater than 20 dB, in order to decrease the field disturbance due to the coupling loop, and smaller than 40 dB, to decrease the effect of thermal noise due to the network analyzer. Hence, a mean value of 30 dB is generally chosen. A third semi-rigid cable, shown in figure 7, is used as a reference line to measure the full transmission power level, i.e the reference level. This cable has a length equal to the total sum of the two cables of the measurement apparatus. The recommended types of semi-rigid cables are UT-1 41 , UT-85 and UT-47 with outer diameters of 3,58 mm, 2,20 mm and 1 ,20 mm, respectively.