STP cable. Analysis of insertion loss degradation in high temperature atmosphere. Taketo Kumada YAZAKI Page 1 12

Transcription

1 STP cable Analysis of insertion loss degradation in high temperature atmosphere Taketo Kumada YAZAKI Page 1 12

2 Agenda IL :Insertion Loss 1 Contents of indications at the last meeting 2 Degradation factors 3 Comparison of calculated value and measured value 4 Calculation of IL 5 Comparison of IL between 23 and IL up to 7.5GHz in 23 and 105 Page 2 12

3 1 Contents of indications at the last meeting IL :Insertion Loss Cable structure 0.13mm 2 Pure copper Cross-linked polyethylene Metal foil + Braided shield PVC Insertion loss Figure 10: Cable structure Contents of indications To explain the reason why the IL remarkably decreases in 105 atmosphere. Based on theoretical formula, the results of actual measurements were verified at this time Initial value 105 atmos. value Down Page 3 12

4 2 Degradation factors Main factors Cable Conductor Skin effect Conductor resistance in temperature change Insulation Dielectric constant Frequency dependence Temperature dependence Dielectric tangent Frequency dependence Temperature dependence Page 4 12

5 Dielectric constant Dielectric constant 2 Degradation factors Dielectric constant:the ease of dielectric polarization of a medium filled between electrodes Types of polarization Electronic polarization Ion polarization Orientation polarization Ex) Ion polarization If polarization is large, the bias of electricity in material is large Frequency dependence Temperature dependence PE(Measured value Frequency Temperature ( ) Page 5 12

6 Dielectric tangent Dielectric tangent 2 Degradation factors Dielectric tangent:electric energy causes molecular motion, it is lost as thermal energy Basic idea :Crystal part :Amorphous part Temperature Tg or less Frequency dependence Tg :Glass transition point Tg or more Temperature dependence Structure and material which are easy to move in the molecule increase the dielectric tangent PE(Measured value Approx times Frequency Temperature ( ) Page 6 12

7 3 Comparison of calculated value and measured 23 atmosphere Measured value Calculated value Influence of suck-out Suck-out 2,200 7,500 More than 2.2GHz are affected by suck-out Measured value and calculated value match up to 2.2GHz Page 7 12

8 4 Calculate IL Formula of Insertion loss Insertion loss(il) = Conductor loss(cl) + Dielectric loss(dl) = Deformation of formula = d Skin effect :Characteristic impedance l :Conductor length r :Conductor radius σ :Electric conductivity of conductor f :Frequency μ :Magnetic permeability of conductor Tanδ :Dielectric constant tangent :Electric resistivity of conductor i.e. Skin effect is taken into account in CL Page 8 12

9 Dielectric tangent 4 Calculation of IL Calculation at 105 atmosphere Conductor resistance in temperature change Temperature dependence of dielectric tangent :Conductor resistance at 23 Temperature dependence :Conductor resistance at 105 Formula of Insertion loss Insertion loss(il) = Conductor loss(cl) + Dielectric loss(dl) Temperature ( ) Approx times + Influence of structure =γ / However, the theoretical formula of IL used in this study does not consider the twist of the conductor, shielding layer or the frequency dependence of the dielectric tangent, etc. Page 9 12

10 5 Comparison of IL between 23 and 105 IL :Insertion Loss CL :Conductor Loss DL :Dielectric GHz DL(Calculated value) 7dB DL(Calculated value) 9dB CL(Calculated value) 15dB CL(Calculated value) 16dB IL(Calculated value) 22dB IL(Calculated value) 25dB IL(Measured value) IL(Measured value) In the case of 105 atmosphere, the influence of DL tends to be large particularly in high frequency band. Therefore the influence of the temperature dependence of the dielectric tangent was also found to be large. Page 10 12

11 6 IL up to 7.5GHz in 23 and atmosphere The above data is downloaded in the private area Page 11 12

12 END Thank you for your attention Taketo Kumada Page 12 12