Test methods for complex permittivity of solid dielectric in microwave frequency band-Method for reentering into gravity
Some standard content:
Electronic Industry Standard of the People's Republic of China SJ/T1014210143-91
Test Method for Microwave Complex Permittivity of Dielectric Materials Issued on April 2, 1991
Implemented on July 1, 1991
The Ministry of Machinery and Electronics Industry of the People's Republic of China issued the Electronic Industry Standard of the People's Republic of China Test Method for Microwave Complex Permittivity of Solid Dielectric Materials Re-entry Cavity Method
This standard specifies the "re-entry" test method for microwave complex permittivity of solid dielectric materials. This method is applicable to the measurement of complex permittivity of solid dielectric materials with time-frequency and micro-frequency. Applicable frequency range: F-(100~1000>MHz, test range 20
tand, - 2 X 10-1 -- 2 X 10-
1 Method and Theory
sT/10143—91
The resonant cavity is a deformation of the capacitor-loaded resonant cavity. Figure 1 shows an electrostatically condensed resonant cavity, whose resonant frequency is determined by the length and the spacing C. When the distance changes, the capacitance C changes, and the resonant frequency changes: when the spacing does not change, but the medium changes, the dielectric constant also changes, and the resonant frequency changes accordingly. Figure 1 Capacitor-loaded resonant cavity
Assume that when the gap is filled with air, the resonant frequency of the resonant cavity is , when a disc-shaped dielectric sheet is put into the gap, the resonant frequency is detuned, At this time, keep the signal frequency unchanged, avoid the inner conductor, and change the distance between the two electrodes to quickly restore the resonance of the cavity. The displacement of the inner conductor is related to the dielectric constant e of the two samples. After the sample is placed, the larger the amount of dielectric constant is, the greater the displacement of the inner conductor will be. According to the sample temperature, the displacement of the inner conductor after the dielectric is formed can be calculated according to the change in the dielectric constant of the cavity. The re-entrant cavity is to move the surface gap capacitance to the middle of the inner conductor, and its structure is shown in the figure. The upper inner conductor can be measured: the lower inner conductor is close to the capacitor gap, and a fine-tuning electrode C is attached: . The Ministry of Electronics Industry of the People's Republic of China has 1 limited C42 batch cells. 12
139:0701 implementation
information
SJ/r10143-91
Figure 2 or the schematic diagram of the test cavity structure
no detection system
when there is no sample in the cavity. fine-tuning thing put a certain initial value (~so the effective position of the mark), the time to the micrometer to make the spectrum oscillate, at this time the measured micrometer number is M: the harmonic data indicates ". Adjust the micrometer to tune the cavity detuning to the output indication is the average power point, the half-power position and corresponding to a certain frequency on both sides, then the value of the empty quality factor 2: can be known.
after collecting the sample, in the sample The capacitance and density loss part of the time change. The main micrometer is used to plan the signal frequency system. At this time, the main micrometer position is M, and the indication is the most harmonic. These parameters can be calculated (tax Im. Thanks for the test plan shown in Figure 3: G No. 2 Test equipment 2.1 Frequency shift signal source Two high-frequency generators:
Yushan power greater than 50mW www.bzxz.net
Fluency stability better than (.02dB/1CmEn
Frequency setting Kang excellent 1x-1/1nin
2.2 Heavy-duty cavity
er upper ha
SI/T 101439:
In the frequency range of 100MHz~1000MHz, the passband can use a cavity, which can be customized by the user. 2.2.1 Size of the resonant cavity
2.2.1.1 Inner conductor
When the parallel plate is excited by a high-frequency field, the transverse voltage conforms to the Bessel surface distribution, and the first equal point is consistent with formula (1). r..(2. 4D52)/(2n)
In order to make the inner conductor have a uniform field, the half of the inner conductor should be less than D.111. Therefore, the diameter of the inner conductor should be less than ten x10-,/width, where is the wavelength of the center frequency, in sm. 2.2.1.2 Inner diameter of the outer conductor
D=(3-~3. 6)d
Where——diameter of the inner conductor,.
2.2.1.3 The cavity length
is about 3/8.
2.2.2 Gap capacitance
The vibration cavity should be designed to be a vibration cavity with a load axis. The end capacitance changes with the movement of the center conductor driven by the detector.
Third, the diameter of the lower inner conductor is less than -6.cm, and the concentricity of the lower inner conductor is less than .2.
The main micrometer is used for frequency data, and the capacitance scale is also used for the inner conductor with side effects, and the through-and-through comparison table is obtained. Here is the main micrometer scale. 2.2.3 Fine-tuning the electric customer
The convex body on the side of the rest is located in the micro-space between the hole and the force. The micro-pass device is used to adjust the frequency. The measurement device is at different positions. The relationship between the reading of the micro-pass device and the frequency is actually the relationship between the broken line - the "right" when the calcium tube is received is introduced again. This can get the slope of the line corresponding to each position of the calcium tube. This is according to the table. 2. 2. 4. The coupling mechanism
Inlet and outlet couplings are all made of ring coupling, and the other door is weakly coupled to the air-conditioning coupling. There is no connection between the two. 2.2.5. Your requirements for the blood inlet cavity
Quality number: 2044-~2500
Main micrometer resolution: 2:10
Use recording A to give a monitoring parameter of a center frequency receiver of 450MH, please check it out quickly. 2.3 Power indicator (or square law wave filter) indicator The sensitivity is not less than 13%. The standing wave ratio is less than 1.1. 2.4 Isolation (1) Depth is greater than 20: Forward and reverse wave ratio is less than 1.1. 3 Test conditions 3.1 Normal test atmosphere temperature, 20~30% 1. Humidity: 45~75℃ Temperature: 86~106kPa ||SI/T10143--91
When testing a sample in reverse, it is carried out under normal test conditions. During the series of measurements, the temperature and humidity should be kept stable.
3.2 Standard atmospheric conditions for the test
Temperature: 25±1°C
Humidity: 48--52°C
Air pressure: 86~106K
4 Samples and their preparation
4. 1. For dielectric materials, the diameter of the dielectric sample should be slightly larger than the inner conductor diameter, so that there is a uniform electric field between the end faces. The diameter of the dielectric sample can be within the inner conductor diameter, 15 mm. 4.2 The dielectric sample diameter is between 3.5 and 6 mm, and is selected according to the different test samples. For materials with larger diameters, the diameter should be selected accordingly.
4.3 The requirements for the quality test rod are as shown in Figure 1
4.2 The sample can be tested only after it has been fully aged and treated. 5 Test procedure
5.1 Do not put in the sample, open the sampling window; 1 point, adjust the capacitor to the initial value of the tester: make the micrometer resonate, and record the reading of the main tester at this time: 5.2 Adjust the capacitor to get the half power level at the micrometer point, and record the readings corresponding to the power points on both sides. At this time, the micrometer is lubricated to the initial state and restored to resonance. 5.3 Put the sample in, close the cover of the sampling window 11, adjust the micrometer to make the alarm respond quickly, and write down the main reading and the alarm indication value.
5.4 From the ~ comparison table, the main micrometer is checked, the near-continuous current and the edge capacitance of the small tower plate are set
5.5 From the ~, the micrometer is adjusted to the locking rate of 4.5.5 From the --M comparison table, the micrometer is in the M position, and the corresponding spectral frequency is obtained. 5.7 At more than 5 different positions around and in the middle of the sample, use a screw micrometer to measure its thickness, and take the average value to get the sample thickness! ：
81/10143—9:
5.B When the material is large, the cavity size design should consider the spacing between the upper and lower inner bodies to maintain the spectrum of the cavity. The light detector uses a high-sensitivity indicator or receiver. If the loading amount leads to a significant change in the degree of fit, the cavity should be considered to include the attenuation of the tangent, and the peak value should be positive.
6 Calculation and evaluation of test results
6.1 Introduction The calculation formula of dielectric constant is: When the sample diameter is 15% larger than the inner conductor diameter, the calculation formula of dielectric constant real part is: +|tt|| Where; tm sample thickness, mm
.… Main micrometer reading when no sample. mm!
M—Local micrometer reading when there is a sample. mm. B.2 Loss single tangent value calculation formula
, K(—)
(2+)Me- M,++
In the formula; & refers to the diameter of the conductor in the cavity, mm!
... Use 4--quantity comparison table to check: the edge capacitance increase when ear ~ Cai to check the table to get M, the edge capacitance increment when: S
The main micrometer reading is the gap between the conductors in the cavity when the penetration is in place, which is a certain value for a cavity description: K is the value obtained when the comparison device is checked!
7 Error reason
When there is no sample, the half-power level on both sides of the harmonic reporting point of the harmonic cavity corresponds to the micro-measurement laser reading, mm harmonic reporting frequency, which is verified by the ~M comparison table: when the number of .MHz1 no sample, the spectrum cavity output power indication is low, when there is a sample, the harmonic output power indication value is reversed, the specified test range is not screened in the domestic test chapter: when 10, /2%;
When 2/road
tano,8un6,/D.15×10-
spectrum cavity integer:
F=450MHzl
cavity height[7mm
inner conductor true diameter=22mml
outer conductor inner diameter D80 mml
sJ/T10143—91
Appendix A
Number of various cavities
(adhesive parts)
The roughness R of the machining surface of the cavity is
The effective stroke of the main electric motor is ~9mm
The resolution of the main micrometer is .00mm
The effective stroke of the micrometer is ~20mml
The resolution of the fine-tuning capacitor is 0.0
The quality number is 2000~2500
Appendix
The calculation formula of n&,
(forbidden parts)
When the product size is small, the calculation formula of and is
(am)
-1- --n-
--(B2)
·(B4)
Body length,
The following is the length of the product, mm.
tar:o,
Additional instructions:
$J/T101-391
d+ dn)* C(M. I --t) -t
This standard is issued by the Ministry of Machinery and Electronics Industry. The standard was issued by Huadong Normal University and drafted by Jianhui Tianxue. The main drafter of this standard is Chu Xuezi, who is responsible for the drafting of the jade edge 18.
....-(B5)
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