lò vi sóng rf

Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P1)

... spectrum is the visible optical spectrum,the ultraviolet spectrum, and x-rays. Below the microwave frequency spectrum isthe radio frequency (RF) spectrum. The frequency boundary between RF and mi-crowaves ... that specific frequency range. Therefore, by extension, the RF/ microwave applications can be referred to as communications, radar, navigation,radio astronomy, sensing, medical instrumentation, ... some of these frequency spectrums are further divided intomany frequency bands as indicated in Figure 1.1. Filters play important roles in many RF/ microwave applications. They are used toseparate...

Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P2)

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... halves with respect to its symmetrical interface.When an even excitation is applied to the network, as indicated in Figure 2.4(a), thesymmetrical interface is open-circuited, and the two network ... building elements in many areas of RF/ microwave en-gineering. Such networks are used to select/reject or separate/combine signals atdifferent frequencies in a host of RF/ microwave systems and equipment. ... chapter to describe various network concepts and provideequations that are useful for the analysis of filter networks. 2.1 NETWORK VARIABLESMost RF/ microwave filters and filter components can be...

Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P3)

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... the same 3 poleButterworth lowpass prototype as that used previously in Section 3.3.1, Figure3.15(b) illustrates a bandpass having a passband from 1 to 2 GHz obtained using theelement transformation.3.3.4 ... = 1 to n (3.24)gn+1= 1.0For convenience, Table 3.1 gives element values for such filters having n = 1 to 9.As can be seen, the two-port Butterworth filters considered here are always sym-metrical ... be chosen.3.2.2 Chebyshev Lowpass Prototype FiltersFor Chebyshev lowpass prototype filters having a transfer function given in (3.9)with a passband ripple LArdB and the cutoff frequency...

Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P4)

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... account by using full-wave EM simulation.4.1.11 Surface Waves and Higher-Order ModesA surface wave is a propagating mode guided by the air–dielectric surface for a di-electric substrate on the conductor ... previous expressions for ␧reareobtained based on the quasi-TEM or quasistatic approximation, and therefore arerigorous only with DC. At low microwave frequencies, these expressions provide ... expressions also provide accuracy better than one percent. If more accuratevalues are needed, an iterative or optimization process based on the more accurateanalysis models described previously can...

Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P5)

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... Semilumped Lowpass Filters Having Finite-FrequencyAttenuation PolesThe previous two types of microstrip lowpass filter realize the lowpass prototypefilters having their frequencies of infinite ... difference lies in the stopband behaviors. The microstripfilter (Design 1) that uses the narrower inductive lines (WL= 0.1 mm) has a bettermatched stopband performance. This is because that the ... EMsimulated performance of the filter.(a)(b)Z0= 50 ohm C1= C7= 3.7596 pFL2= L6= 11.322 nH C3= C5= 6.6737 pFL4= 12.52 nHThe microstrip filter design uses a substrate having a relative...

Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P6)

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... active RF components in such a way that the RF be-havior is not affected at all by the dc connection. Referring to Figure 6.15(a), theconnection of the bandstop filter should not affect the RF ... lowpassprototype.(a)(b)performances in Figure 6.13(b) and Figure 6.14(b), the optimum design demon-strates substantially improved performance with a steeper stopband response.6.2.4 Bandstop Filters for RF ChokesA ... desiredstopband for RF choke. A quarter-wavelength inductive line at the input of a band-stop filter is necessary for transforming an RF short circuit resulting from a radialstub into an RF open circuit...

Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P7)

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... (MEMS) provide a class of new devices and com-ponents which display superior high-frequency performance and enable new systemcapabilities. For a general definition, a MEMS is a miniature device ... this point, it is worthwhile comparing the surface resistance of HTS with thatof normal conductors. For a normal conductor, the surface resistance and surface re-actance are equal and are given ... finite thickness of thin film tends to increase boththe surface resistance and the surface reactance of thin film. Figure 7.4 plots thesurface resistance of the thin film as a function of t/␭,...

Tài liệu Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P8) doc

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... of S11in (8.76)is always equal to 1. This is because in the vicinity of resonance, the parallel res-onator of Figure 8.11 behavior likes an open circuit. However, the phase response ofS11changes ... effect if their signs are opposite. Obviously, the direct evaluation of the cou-pling coefficient from (8.31) requires knowledge of the field distributions andperformance of the space integrals. ... ofKirchhoff’s two circuit laws and states that the algebraic sum of the currents leavinga node in a network is zero, with a driving or external current of isthe node equa-tions for the circuit of Figure...

Tài liệu Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P9) doc

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... all the numerical methods, is due to the fi-nite cell or mesh sizes. These EM simulators divide a RF/ microwave filter structureinto subsections or cells with 2D or 3D meshing, and then solve ... superconductors can give better performance of filters, but isnormally more expensive. This may then be evaluated by a cost-effective factor interms of the performance. Labor costs include those ... 9.22 Performance of the filter in Figure 9.21. (a) Computed. (b) Measured.(a)(b)9.2.3 Artificial Neural Network Modeling Artificial neural network (ANN) modeling has emerged as a powerful CAD...

Tài liệu Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P10) pptx

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... theimprovement in selectivity over the Chebyshev filter is evident. The closer the atten-uation poles to the cut-off frequency (⍀ = 1), the sharper the filter skirt and thehigher the selectivity.⍀aFBW ... constant of 10.8. (b) Measured performance of the mi-crostrip CQ filter.(a)(b)loss LR= 20 log|S11| in dB, and n is the degree of the filter. It is obvious that ⍀ =±⍀a(⍀a> 1) are ... [17].10.5 LINEAR PHASE FILTERSIn many RF/ microwave communications systems, flat group delay of a bandpass fil-ter is demanded in addition to its selectivity. In order to achieve a flat group...

Tài liệu Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P11) ppt

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... even without the via hole grounding. Thus, it would seem that the voltageand current distributions would not change much in the vicinity of the midband fre-quency, even though the via holes are ... the electromag-netic energy efficiently as far as its occupied surface area is concerned. This is be-379Microstrip Filters for RF/ Microwave Applications. Jia-Sheng Hong, M. J. LancasterCopyright ... designed ona RT/Duroid substrate having a thickness of 1.27 mm and a relative dielectric con-stant of 10.8. Figure 11.9 illustrates the layout and the EM simulated performanceof the filter. This...

Tài liệu Microstrip bộ lọc cho các ứng dụng lò vi sóng RF (P12) pptx

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... stationsvary but may focus on increasing sensitivity and selectivity: ț Sensitivity—The benefits of increasing sensitivity in rural areas is obvioussince the number of mobile base stations and ... otherside of the RF module. The RF module for three channel HTS microstrip duplexersis shown in Figure 12.3. The diameter of the RF modules is only about 150 mm. Thedesigns and performances of ... MicrostripDuplexerNon-HTS MicrostripCircuitFIGURE 12.3 RF module with three channels of HTS microstrip duplexers. CompressorEncapsulated RF ModulesFIGURE 12.4 Encapsulated RF modules on the Stirling cooler with...

Tài liệu Lò vi sóng RF và hệ thống không dây P1 docx

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... variousservices such as voice mail, email, video, messaging, data, and computer on-lineservices. The direct link between satellites and personal communication systems canprovide voice, video, ... to cable television, and the end of the Cold War has made many militarytechnologies available to civilian applications. The global positioning systems(GPSs), RF identi®cation (RFID) systems, ... in the United States, including televisions,radios, satellite communications, cellular phones, police radar, burglar alarms, andnavigation beacons. The performance of each application is strongly...