2 Radome Design Elements. 4. Mechanically,. Storage (G') and loss (G") modulus as well as loss tangent of two extruded LDPE 3020D samples measured by dynamic mechanical analysis at T = − 150 to 100 °C and frequency of 1 Hz Fig 16 and 17 show the storage and loss moduli as well as the damping factor of two specimens of LDPE 1840H and 3020D samples in the temperature. 1 and loss tangent as low as 0. 23 and 0. View PDF View article View in Scopus Google. 3. 4 GHz) using waveguide cavity. 1, its loss tangent is 0. 1. Benefits. 1, low dielectric loss tangent∼10 −4) and excellent thermal stability [19]. 14. It has been reported that 60 wt. 0020 5 15 25 35 45 55 65 Loss Tangent Frequency (GHz) PTFE Teflon® Type A L=4. 1, low dielectric loss tangent∼10 −4) and excellent thermal stability [19]. 20° indicating a highly crystalline form of pure AgNO 3 and several other low-intensity salt peaks at 19. It can be clearly seen that the profile of -NRW in Fig. laminates are woven fiberglass/PTFE composite materials for use as printed circuit board substrates. Larger error bars due to stability of lab ambient temperature. 1550, UL 94 V- 0, USP Class VI. It doesn't mean that you don't have this property in any other types of circuit. 1) Ultra Low Loss Tangent & Dissipation Factor Since the dielectric in CuFlon is pure PTFE, the losses are lower than those encountered in PTFE/glass materials. Copolymers of tetrafluoroethylene and hexafluoropropylene showed two dielectric loss peaks: one. 2-2. PTFE loss tangent AFM study: (a). 1% moisture absorption is ideal for packaging materials . For the simultaneous analysis of both thermal conductivity and dielectric properties according to the PTFE content, the in-plane and through-plane thermal conductivity, permittivity, and. 011: GOOD Dielectric Constant 4. Each experimental setup has three main parts: water reservoir, DNAPL reservoir and main column (porous medium). moulding medium viscosity acetal resin for injection moulding. 0017 is employed. However, it is explained in. 2) E 1080 B RC SC Reinforcement Type (see 1. 0; C. 00 10 3 at 10 kHz. When the testing frequency is increased to 1 kHz, β-PVDF. The coefficient of sliding friction between PTFE and many engineering materials is extremely low and when sintered with wear reducing compounds, an industrially important class of bearing materials are formed. 1 0. Most plastics have relatively lower dissipation factor at room temperature. PTFE loss tangent was set to zero, as the realistic loss tangent of PTFE is extremely small anyway, and the shortness of the line further reduces any significant losses in the coaxial line. e. Rick Lovelady. Phys. PTFE is chosen as polymer matrix because of its excellent dielectric properties (low relative permittivity∼2. Low values of Df result in a “fast” substrate while large values result in a “slow” substrate. 0021 E-2/105Loss Tangent – Approximately 0. 3 and 0. rick@matrixusa. 5" 0. The increased thermal conductivity provides higher power handling, reduces hot-spots and improves. In the case of cement–matrix composites, both loss tangent and storage modulus are greatly enhanced by the addition of silica fume. 5 S/m. The lower the dissipation factor, the more efficient is the insulator system. If tanD is zero, there is no loss due to dielectric. Df, Loss Tangent A. Thermally, solid PTFE dielectrics have a sharp knee in their CTE profile around room temperature. The ε of the PTFE composite film (PTFE/BN/m-AlN) with 90 wt% filler content was only 3. 001 to 0. PolyEthylene, DE-3401. The permittivity and loss tangent are measured using a narrow sweep of frequency around the target or desired frequency. 66-78. The loss tangent creates. It was reported that <0. The low dielectric constant and low loss tangent make SiO 2 a very low-loss material for microwaves. Polymers are important dielectric materials that are often used for a wide range of applications, including high-energy-density capacitors 1,2,3,4,5,6,7,8,9, high-voltage cables 10. Therefore, to low the dielectric loss of the composite, the silane coupling agent F8261, which is similar to PTFE and has a long C–F chain, was chosen as a surface modifier to hydrophobized the GF. 008 87 Loss modulus (MPa) 336 ±70 375 ±83 Evaporation PTFE Panel. RO3000 Series laminates are circuit materials with consistent mechanical properties, regardless. 009 to 0. 0014-. RT/duroid® high frequency circuit materials are filled PTFE (random glass or ceramic) composite laminates for use in high reliability, aerospace and defense applications. They have dielectric constant (Dk) of 3. 1. CuClad® laminates are woven fiberglass/PTFE composite materials for use as printed circuit board substrates. Jacket FEP, Tan 0. 1. For the fused silica and Sapphire wafers, the loss tangent increases slightly as a function of. 7. PTFE is a soft substance can it can be easily distorted; Then there is the cost. c. RF-35TC offers a "best in class" low dissipation factor with high thermal conductivity. Resonac considers the difference between SFR and LCP as the difference in dielectric loss based on Dk and Df. Prepreg. 67), and R - specific resistance. 1 and 0. 2. 3. Phys. Download scientific diagram | Test results for the dielectric constant and loss tangent of PDMS-Al2O3-PTFE materials with different doping ratios. PTFE also has a very low loss tangent with a typical value of tan δ = 4 × 10 −4 , which decreases by a factor of 2-3 from 300 K down to 4 K [51, 52]. 001 to 0. The CuClad 6250 bonding film is available in both 24” (610mm) roll form and sheeted format. 5. Dielectric Loss and Copper Loss . Thus,. The washed PTFE sheets were then dried using. This family of advanced laminates offers exceptional electrical and mechanical stability. Thermal. 5 GHz at room temperature and also for temperatures varying from –30°C to 25°C at a frequency of 3. 195" RG 400 Loss (Attenuation) & Power. 85 at 20 GHz (Fig. This paper presents a method for reducing dielectric loss (tan δ) by forming PDMS composites loaded with various concentrations of either alumina (Al 2 O 3) or polytetrafluoroethylene (PTFE). Chemical structure of PTFE. Rogers RO3000 high frequency circuit materials are ceramic-filled PTFE composites intended for use in commercial microwave and RF applications. The more common compounded PTFE grades are filled with glass fibre, bronze, graphite, carbon. RT/duroid® 5870 and 5880 glass microfiber reinforced PTFE composites are designed for exacting stripline and mi crostrip circuit applications. Where data were available, the loss tangent for PTFE (Teflon) reported were all close to zero (at least as small as about 10 −3), same as those we obtained here. PTFE Teflon® Type A L=4. Dielectric constant ((varepsilon_{r}')) and loss tangent (tan δ) of filled composites at microwave frequency region were measured by waveguide cavity perturbation technique using a Vector. XRD patterns of pure AgNO 3, pure PMMA, pure PVdF, different wt% ratios of PMMA and PVdF with constant AgNO 3 (5 wt%) are shown in Fig. Successful Design of OC-48/2. The cells were 5. The conductivity of PTFE/CNT (5 wt%) nanofiber membranes reached 1. 5 ¥ 10-3 at 60 GHz which exhibits significant impact on total loss in mm-Wave device but the processing for PTFE is also known to be difficult. 6 Report the average permittivity and loss at the frequen-RO4003C laminates provide tight control on dielectric constant (Dk) and low loss while utilizing the same processing method as standard epoxy/glass but at a fraction of the cost of conventional microwave laminates. Wang) The discussion in this section has assumed that [Math Processing Error] ϵ c is complex-valued solely due to ohmic loss. My Research and Language Selection Sign into My Research Create My Research Account English; Help and support. 8 Loss Tangent 0. PTFE L-5 and PTFE JH-220 powders showed good dispersion in the PBS matrix, and PTFE FA-500 powder underwent fibrillation during the melt blending process. 8°,. 8 Loss Tangent 0. 54*10-5. The dielectric permittivity and loss tangent were acquired using a precision impedance analyzer (Agilent 4294A) under the electric voltage of DC 0. in terms of the loss tangent • Loss increases directly proportional to frequency 30 C G D. They exhibit excellent chemical resistance, including solventLow dielectric loss is important for a good capacitors and insulation. 5. The density, dielectric constant, loss tangent, moisture absorption and ultimate tensile strength of the composite systems under study are complied in Table 1. 33 x 10 7: MΩ-cm. 0015 0. Where tan δ is the dielectric loss factor of the substrate and f is frequency. 1. Loss Tangent. The raw materials used were PTFE aqueous dispersion (TE-3865C, DuPont, USA) and fused amorphous SiO 2 powder (≥99. 3 GHz and 5. Surface resistivity. Values presented here are relative dielectric constants. 0 ()1. Loss tangent (tan δ) of all samples was measured at a heating rate of 3 °C/min and a frequency of 1 Hz in the temperature range from − 140–150 °C. RF & Microwave Design Guide 8 Chapters - 44 Pages - 60 Minute Read . 3 to Equation 3. PTFE is ideal for this role because it has both low relative dielectric constant and low dielectric loss tangent; however, PTFE does not like to stick to things. A surface roughness is very low for PTFE substrate and there is low reliability inRogers RT/duroid 5880 high frequency laminates are PTFE composites reinforced with glass microfibers. Additionally, as shown in [14,15] fleece fabric provides sufficient thickness for an adequate bandwidth. PTFE or Polytetrafluoroethylene is a versatile and high-performance fluoropolymer made up of fluorine and carbon atoms and is highly used as a non-stick coating in kitchen. BNT/PTFE. The increment in complex permittivity with increasing rFe 2 O 3 nanofiller can be attributed to the polarization process due to the enhanced conductivity and interfacial polarization in the composite and hopping exchange of charges between localized states [ 23 ]. Polytetrafluoroethylene (PTFE) has been widely used in packaging and substrate industries because of its very low dielectric constant and excellent chemical resistance. RT/duroid 5880 laminates has a low dielectric constant (Dk) and low dielectric loss, making them well suited for high frequency/broadband applications. Example 6-layer stackup with a PTFE laminate on the outer layer and FR4 laminates on inner/bottom layers. 009 to 0. Sci. An intermediate layer is often used between PTFE and copper to improve the adhesion, but using these layers is a tradeoff because they increase insertion losses. 2. 물질의 유전율은 보통 상대 유전율, 즉 진공의 유전율에 대한 상대적인 값 로 나타낸다. 09 (TDS); whereas the loss tangent angles are ~7. Polytetrafluoroethylene (PTFE) has an extremely low loss tangent (tan δ = 0. Rogers CLTE-XT laminates are composites of micro-dispersed ceramic filler, PTFE and woven fiberglass reinforcement, designed to improve loss tangent while maintaining good dimensional stability. Among the polymers, polytetrafluoroethylene (PTFE) is the most preferred host matrix that exhibits excellent dielectric properties such as low permittivity (ε r = 2. 094 in 2. The flexibility of TLY-3FF is comparable to chopped fiber reinforced PTFE laminates yet it has a loss tangent that is lower than traditional chopped fiber reinforced laminates. PTFE has become the material of choice where low friction, excellent thermal properties, chemical inertness, and exceptional dielectric properties are required. Article. This stability simplifies the design of broadband components and allows the. Teflon PCBs transmit signals of 5GHz and higher frequencies. 3 respectively. 1 and extremely low loss tangent tan δ ∼ 0. The dielectric constant of the presented stack up remains stable around 4. 37 shows an idealized radome. The comparison of the PTFE/recycled BRS composite at a filler size of 63 μ m with commercial high-frequency laminates is presented in Table 3. Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum. Specifications Met: ASTM D1710, FDA Compliant 21 CFR 177. , the central and the outer conductor, were modeled as perfect electric conductor (PEC). Dielectrics with low loss provide reduced attenuation and heating in circuits. 011: GOOD Dielectric Constant 4. Among these polymers, polytetrafluoroethylene (PTFE) has caused concern of the industry and academia, due to its excellent dielectric properties such as low permittivity, extremely low loss tangent [1, [5], [6], [7]]. Accurate measurement of the permittivity and loss tangent of low-loss materials is essential due to their special applications in the field of ultra large scale integrated circuits and microwave devices. 5 Repeat 5. 1 50-170 - 0. 009: BETTER Dielectric Constant 3. 012 at 1 MHz, respectively. 2. Center Conductor: 0. Loss tangent (tan (δ)) is a measure of signal loss as the signal propagates down the transmission line. e. The result is much lower loss at microwave frequencies than solid PTFE offers. 0010 to 2. The MEGTRON 7 family, including MEGTRON 7(N), MEGTRON 7(GE) and. The effect of loss tangent on properties of dipole antenna was studied for values 0. Loss tangent can be calculated using the following formula: tanδ=1/(ω*ε v *ε 0 *R), where ω - circular frequency, εv - dielectric constant of vacuum (8. 2 for comments on expected behavior for permittivity as a function of frequency. 5%) 0. 128 at 2. 5–26. 5 x par t thickness Impor tant Notes: 1) Processing conditions quoted in our datasheets are typical of those used in our processing laboratoriesPTFE sheets were sequentially washed with acetone (99. 0003, and it also has a relatively high service temperature (∼250 °C) [14], [15]. % filler loading. 02 and a loss tangent of 0. The randomly oriented microfibers in the PTFE composites result in exceptional Dk uniformity. Losses are of two. 1885 0. 2123. 45 GHz. 6 to 1. 8 THz. The mass loss of 10. Despite relatively high signal loss and low thermal rating, FR1 PCB offered a low-cost material choice. Therefore, PEEK/PTFE-5 had much higher dielectric loss than that of PEEK-PFN-5 with the same fluorine content. 0005 0. 2: Loss tangent defined in terms of the real and imaginary components of the complex permittivity [Math Processing Error] ϵ c. 2 dB with a thickness of 2. 5 × 10⁻³ at microwave frequencies (around 10 GHz). While sintering first evaporate the binder at 500-600 for 15 min and then go to your desired temperature. 8 rad/s, or ω = 10 rad/s corresponds to f = 1. PTFE is often used in high-frequency and microwave applications due to its low signal loss and superior electrical performance. The resultant loss tangent of epoxy resin–barium titanate composite at 5 GHz is shown in Fig. Electrical strength. 2E-4 @100 MHz. Teflon is the brand name that Dupont Corporation uses for its PTFE materials, and it is so well-known that people use Teflon PCB to refer to PTFE substrate PCBs used for. In the low loss tangent of PTFE is explained as a consequence of the symmetrical conformation of the polymer backbone, which neutralizes the dipole forces of the C–F bonds yielding a net zero dipole moment. 9. Fig. 59%, the loss tangent was slightly enhanced due to pore-induced polarization. The loss tangent values are what you’d expect compared to typical FR4 materials (about a factor 10 lower), and these materials have high decomposition temperatures compared to typical FR4 laminates. 2. The dissipation factor remained constant, being about 2 × 10 −5. The first column on the left sums-up the basic data of virgin PTFE G400, in order to compare with the values of the. Silicon dioxide-filled semi-rigid coax cables can withstand temperatures that would cause PTFE-filled cables to catch on fire! S No Material Dielectric constant Loss Tangent 1 Unreinforced PTFE, Cuflon 2. Products Why Isola Why Isola Materials Quality. , their dielectric constants are not dependent of the frequency as electronic polarization is instantaneous regardless of frequency. traditional PTFE substrates. stant ("0) and the dielectric loss tangent (tan ) by the following equation (1). The formula to calculate the dissipation factor of an insulator is as follows: Where: DF is the dissipation factor or loss tangent; δ is the phase angle between the voltage and current waveforms in the insulator; I R is the resistive current; I C is the. an insulating material, breakdown of that materials molecular 2. 6 for the entire band while loss tangent varies from 0. One of the efforts to control the CTE of PTFE. Mechanically, low loss, low density dielectrics are nearly as compression. Polyolefin, irradiated. , 44 (2018), pp. 4" L=10. The dielectric loss which is also an important parameter for the circuit application of composite substrates was affected by the loss tangent of each component and the manufacture process. Volume resistivity. Key applications include long antennas and radar applications for automobiles, such. 15–3. 0007 1017 1018-1019 Polytetrafluoroethylene filled with Glass PTFE 25% GF - 2. Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum. Toray's full suite of lightweight syntactic foams is compatible with our low dielectric, pure radome prepregs, offering a weight-saving tuned system solution. You can expect significant performance variations from one assembly to the next. 9) Resin (see 1. τ ε rPolymer Composites is the engineering and scientific journal serving the fields of reinforced plastics and polymer composites including research, production, processing, and applications. 4 for all desired frequencies. How can I define this new material in CST? It is noteworthy that the material has complex permittivity. Download : Download high-res image (357KB)Furthermore, this substrate also displayed low loss with loss tangent of 0. 46 and 2372. Dielectric: Solid Polytetrafluoroethylene (PTFE) Shield (Outer Conductor): Double Silver Covered Copper Shields; Jacket: Flourinated Ethylene Propylene (FEP) Type IX per MIL-C-17; RG 400 Diameter. Alternative material systems use PTFE-based laminates and bondply materials to bond a PTFE layer with the next layer in your PCB stackup. Low dielectric loss and low-cost recycled borosilicate (BRS) glass-reinforced polytetrafluoroethylene (PTFE) composites were fabricated for microwave substrate applications. 1 Lossy Dielectrics. 1 Understanding Dielectric Constant and Loss tangent on Radome and Antenna Design Loss Tangent =. Electromagnetic simulations demonstrate that both the resonant frequency and quality factor of the sensor vary considerably with the dielectric constant and loss tangent of the liquid sample. 1, 0. , Ltd. The use of composite engineering to tailor structural composite materials for damping results in enhancement of the loss tangent, with negligible, if any, reduction of the storage modulus. 1Thermally conductive low loss laminate. 008") Dielectric Diameter: 0. constant of 2. 4 a–b. 3). Good dielectric properties with values of εr = 11. To achieve polytetrafluoroethylene (PTFE)-based composites for high-frequency applications with low dielectric constant, low dielectric loss tangent and low coefficient of thermal expansion (CTE), a novel pentafluorostyrene (PFS) interface modifier was used to achieve excellent performance for SiO 2 /PTFE composite materials. An optimal pore size range enhanced the dielectric properties, beyond which a lower loss tangent was exhibited. Ultra-low Loss, Highly Heat Resistant Circuit Board Materials. 9 mm] . 045 (2. Thus, loss tangent provides an alternative way to quantify the effect of loss on the electromagnetic field within a material. As shown in Fig. PTFE Teflon® Type A L=4. It is a solid form of fluorocarbon and a compound with elevated. Where α (dB/m) and ε r are the signal transmission loss and the dielectric constant of the substrate. 45 MPa) and bending modulus (522 MPa), better thermal. 1: Permittivity of Some Common Materials is shared under a CC BY-SA 4. 6 Thermal stability of AlN/PTFE composites. 1. 2. 25) and dielectric loss (tanδ of 0. 1, low dielectric loss tangent∼10 −4) and excellent thermal stability [19]. A surface roughness is very low for PTFE substrate and there is low reliability in Rogers RT/duroid 5880 high frequency laminates are PTFE composites reinforced with glass microfibers. Helping to maintain the Dk uniformity are the randomly oriented microfibers reinforcing the. 224 ± 0. 0005 0. 0 license and was authored, remixed, and/or curated by Steven W. Spacing between the radar antennas and the radome:PTFE-based ceramic-polymer dielectric composites have been widely researched in the communication field due to their good processing, wide range frequency and temperature stability and being able to provide tunable dielectric constant in a scale. Published in: 2006 International Conference on Microwaves, Radar & Wireless CommunicationsFigure 6. PTFE has a lower dielectric constant (Dk) and loss tangent (Df) than commonly used low-loss thermoset materials. In. A certain SiC, Si, and PMMA powder mass was weighed. ER=4. 09 (TDS); whereas the loss tangent angles are ~7. 실제 유전율은 상대 유전율에다 진공의 유전율 를 곱해서 구할 수 있다. 5 THz to 0. PTFE Loss tangent 0. quality factor. BZV-filled HDPE composite shows a εr value of 4. The Lynch formula [1] can be used to predict the change in Loss tangent loss Rule of Thumb #116. 46 and 2372. These materials have lower loss tangent than FR4 materials, so signals can travel farther without attenuating and still fall within acceptable margins. 1), extremely low loss tangent (tg δ = 10 −4 at 1 GHz), corrosion resistance, excellent chemical resistance, and is stable in a wide range of frequencies [8], which make it a. 9, dielectric loss of 0. Likewise, relative permittivity is the ratio of the capacitance of a capacitor using that material as a dielectric, compared with a similar capacitor that has vacuum as its dielectric. See. North America Asia Europe IsoDesign Tools Contact Us. 00155 whereas for nano Sm2Si2O7 composites with same volume fraction the values. Megtron 6 provides designers significant benefits in system performance for telecommunications applications, routers/switching equipment, high-speed transfer and computing applications. Here’s a short list of some dimensions you might look at when selecting an RF PCB substrate material. This carefully controlled ratio provides a higher dielectric constant (Dk) range and better dimensional stability and. Dielectric Loss (see 1. measure the microwave dielectric loss tangent of a variety of materials. LaminateR-5785(N)/Prepreg R-5680(N) The ultra-low dielectric constant (Dk) and dissipation factor (Df) make MEGTRON 7 ideal for high speed and large data volumes associated with servers and routers required for 5G. 081 at 100 GHz and 2 THz, respectively. 44 × 10 −3, respectively, by the improved free-space. 1. Wide dielectric constant range available: 2. It can be seen from the figure that as a function of filler loading, loss tangent also increases. 25 vf micro Sm2Si2O7 composites showed a relative permittivity and dielectric loss of 3. 6. 41 Coefficient of Thermal Expansion 17 18 Y ppm/˚C --55˚C to 288˚C IPC TM-650 2. 1 shows a schematic layout of the cell and the column used in this study. This paper presents a fast and easy to use method to determine permittivity and loss tangent in the frequency range of 75 to 325 GHz. 94 +/- . 56 cm long with the internal diameter of 5. Variation in loss tangent of rFe 2 O 3 –PTFE nanocomposites. 100 ±0. 18 and 0. Generally, when selecting a dielectric material during the design process, two parameters are considered. The average insertion loss for CPW lines at 40GHz. It is a measure of the amount of energy loss from the material due to an external electric field. 5% transmittance at these Fabry-Pérot resonance frequencies [34], due to. When the resin. The surface of SrTiO 3 powders were successfully coated by silane coupling agent (vinyltrimethoxysilane, VTMS). When sticking to these guidelines, it should be possible to design a radome that causes less than 2 to 3 dB loss. 0000 0. 3 TiO 3 (CNT) ceramic possesses both high dielectric constant ( εr ~100) and low loss tangent (5. @ 2 GHz. signal and includes both dielectric and dc-conductivity losses. 1 at 10 GHz (Fig. The composites possess great thermal conductivity and high bending strength. 156" Overall Diameter: 0. TheFebruary 27, 2020. Dielectric Loss =. 3. PTFE has dielectric constant of 2. 008 87 Loss modulus (MPa) 336 ±70 375 ±83 Storage modulus (GPa) 3. and it influences cost of devices. 4 times higher dielectric loss tangent and effective relative dielectric permeability compared to unmodified. The conductivity of PTFE/CNT (5 wt%) nanofiber membranes reached 1. Combined with ultra-low dielectric constant and dielectric loss, FEP/PTFE nanocomposite foam has great potential to be applied in next generation communication devices. a) Dielectric loss (in dB per unit length, length is in the units used for λ. Stretching is more important at lower frequencies and data rates, which affects the trace. PTFE and PES Structure, Electrical Properties and Test Method Prior to the evaluation of different formulation strategies to develop a new low loss material, the first step involves a thorough evaluation and understanding of the loss measurement test methodLow dielectric loss (RO3003™ laminates) • Laminates can be used in applications up to 77 GHz. Hence, in this paper, PTFE and spherical CNT were chosen as polymer matrix and ceramic filler, respectively. However, the main disadvantage of PTFE is the negative temperature coefficient of dielectric constant (τ ε ∼-400 ppm/°C) making it difficult to be used in microwave circuit devices. Another blended polymer prepared from PEEK and PTFE (PEEK/PTFE-5) possessed a dielectric constant of 3. 11 at 3. Loss tangent versus temperature at 1. , the maximum dielectric loss tangent is 0. 49 ±0. 11) Reinforcement (see 1. Loss tangent, storage modulus and loss modulus of various polymers. 17 to 2. 55, a loss tangent less than 0. 059 at 0. 6 (c)), which was due to the porous structure formed by the volatilization of additives during sintering. Unlike PTFE based high performance materials, RO4000 series laminates do not require specialized via preparation processes such as sodium etch. Table 3-Dielectric Properties Vs. 1. The decrement in filler size from 106 μm to 25 μm also increased the mean dielectric constant and loss tangent of the composites from 2. Novel high dielectric constant and low loss PTFE/CNT composites. Both twisting and bending lead to structural deformation, namely the density distribution change of the PTFE SCPDW at the bending section, which affects the dielectric constant and loss tangent. 038 87Dissipation factor is the tangent of the loss angle of the insulating material. Dielectric Loss =.