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Tài liệu RF và mạch lạc lò vi sóng P1 ppt

... theappendices. Chapter 2 provides an overview of wireless communication systems andtheir characteristics.8INTRODUCTIONTABLE 1.4 Selected Applications of Microwave Solid-State DevicesDevices Applications ... carry the video information as well. Table 1.1 shows thefrequency bands used for commercial radio and television broadcasts.In the case of digital transmission, a standard monochrome television ... terrestrialcommunication system.Figures 1.3 and 1.4 list selected devices used at RF and microwave frequencies.Solid-state devices as well as vacuum tubes are used as active elements in RF andmicrowave...

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Tài liệu RF và mạch lạc lò vi sóng P2 pdf

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... illustrated in Figure 2.7. Amicrowave signal generated by the oscillator is split into two parts via the powerdivider. The circulator feeds one part of this power to the antenna that illuminates atarget ... Dopplerfrequency if the target is moving. Note that the signal travels twice over the samedistance and, therefore, the Doppler frequency shift in this case will be twice thatfound via (2.4.33). Mathematically,oo ... on-boardelectronics before transmitting it back. The gravitational force needs to be balancedsomehow if this object is to stay in position. An orbital motion provides thisbalancing force. If a satellite...

Tài liệu RF và mạch lạc lò vi sóng P3 docx

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... converted to correspondingimpedance by moving to a point on the diametrically opposite side of the VSWRcircle. It shows a normalized load impedance as 2  j2. Moving from this point by3.15 l toward ... transformer is also presentedalong with a few examples to match resistive loads. Impedance measurement via thevoltage standing wave ratio is then discussed. Finally, the Smith chart is introducedto ... Solutions to the transmission line equation are thenconstructed in order to understand the behavior of the propagating signal. This isfollowed by the concepts of sending end impedance, re¯ection...

Tài liệu RF và mạch lạc lò vi sóng P4 docx

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... 3417,respectively.Substituting these into (4.5.5), Q of this cavity is found to be 2106.Circular Cylindrical CavitiesFigure 4.20 shows the geometry of a circular cylindrical cavity of radius r and heighth. It is ®lled ... CIRCUITSIf the cavity is made of a perfect conductor and ®lled with a perfect dielectric thenit will have in®nite Q. However,it is not possible in practice. In the case of cavitywalls having a ®nite ... ac3mrerr4:5:2Permittivity and permeability of the dielectric ®lling are given by e and m,respectively; o is angular frequency; and Rsis the surface resistivity of wallswhich is related...

Tài liệu RF và mạch lạc lò vi sóng P5 pptx

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... re¯ection coef®cient of 0.2 isacceptable, circuits (iii) and (iv) can provide much wider bandwidth in comparisonwith those of the previous example. This concept can be used to shape the re¯ectioncoef®cient ... between them. This device can be inserted at aconvenient point before the load. The impedance is matched by adjusting thelengths of the two stubs. Of course, it does not provide a universal solution. ... 36:6269 O; Cs 4:3453 pFand,Xp 91:29009 O A Cp 1:7434 pFExample 5.10: Reconsider the previous example where YL 8 À j12 mS is to bematched with a 50-ohm line. Complete or verify the...

Tài liệu RF và mạch lạc lò vi sóng P6 ppt

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... characteristic impedance versus normalized length of thetaper.This design can be achieved by moving the zeros at u Æ1 and Æ4 into thepoints Æ2 and Æ3, respectively. Hence,QuCu2À 222u2À ... Hence,GinL0dGin12L0eÀj2bzddzlnZdz 6:7:3Therefore, Gincan be determined from (6.7.3) provided thatZz is given. However,the synthesis problem is a bit complex because, in that case,Zz ... meet suchrequirements. The chapter begins with the single-section impedance transformerthat provides perfect matching at a single frequency. Matching bandwidth can beincreased at the cost of...

Tài liệu RF và mạch lạc lò vi sóng P7 pptx

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... Zo2Z2 Zo2b2a27:6:22Dividing (7.6.17) by a1and then using (7.6.21), we ®ndb1a1 G1Z1À Zo1Z1 Zo1 S11 S12a2a17:6:23Now, dividing (7.6.18) by a2and then ... jb, the network becomes lossless. In that case,S11S12S21S22 !0 eÀjb`eÀjb`0 !Obviously, it is a unitary matrix now.Example 7.19: Find scattering parameters of the two-port network ... illustration).280TWO-PORT NETWORKSCurrent through 0.1 S is I1À IN 0:0692V1. Using the current division rule,current IMthrough 0.2 S is found as follows:IM0:20:2  0:0250:0692V1 0:0615V1AHence,...

Tài liệu RF và mạch lạc lò vi sóng P8 ppt

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... devise some way to control itsattenuation around the cutoff. Expression for the propagation constant of a T-sectionis listed in Table 8.1. In order to ®nd g of this T-section, we ®rst divide ... two-port network. Filters have been designed using active devices such astransistors and operational ampli®ers, as well as with only passive devices (inductorsand capacitors only). Therefore, these ... the load and source resistances are at 75 Oeach.The low-pass ®lter designed in Example 8.7 provides the initial data for this high-pass ®lter. With m  3; gL 0:62425, and gC 0:9662, we...

Tài liệu RF và mạch lạc lò vi sóng P9 docx

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... SIGNAL-FLOW GRAPH REPRESENTATION OF A PASSIVESINGLE-PORT DEVICEConsider load impedance ZLas shown in Figure 9.18. It is a single-port device withport voltage and current VLand IL,respectively. ... ZSZoVrefS ESÀ 1ÀZSZoVinSor,VrefSZoZo ZSESÀZoÀ ZSZo ZSVinSDividing it by2Zop,we ®nd thatVrefS2ZopZoZo ZSES2ZopÀZoÀ ... ZLZoVrefLZLZoÀ 1VinL9:3:1or,VrefLZLÀ ZoZL ZoVinL ÀLVinL9:3:2After dividing it by2Zop,we then use (7.6.15) and (7.6.16) to ®nd thatbL ÀLaL9:3:3where,bLVrefL2Zop9:3:4aLVinL2Zop9:3:5and,ÀLZLÀ...

Tài liệu RF và mạch lạc lò vi sóng P10 docx

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... Since Goisapproximately 14 dB, the remaining 2 dB can be set via GSand GL. If we design aninput-matching network that provides GSas 1.22 dB then we need an output-matching network for ... values of load or source impedance) if one or both of these conditions areviolated. It means that the transistor can provide stable operation for a restrictedrange of GSand GL. A simple procedure ... blocks of an electronic system. Whilevacuum tube devices are still used in high-power microwave circuits, transistorsÐsilicon bipolar junction devices, GaAs MESFET, heterojunction bipolar transistors(HBT),...

Tài liệu RF và mạch lạc lò vi sóng P11 ppt

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... nonlinear active device. In addition, since thedevice is producing RF power, it must have a negative resistance.The basic principle of an oscillator circuit can be explained via a linear feedbacksystem ... the active device at the frequency ofoscillation. These two conditions are complementary to each other; i.e., if condition(11.7.1) is satis®ed then (10.7.2) is also satis®ed, and vice versa. ... radiansper second per volt.Mixer 1 Change of output phase equals change of inputphase.Divider1NN is the division ratio.Phase detector KdKdis the slope of phase detector voltage to phasecharacteristic...

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, ... Chapter 2 reviews some fundamentalprinciples of transmission lines and electromagnetic waves. Chapter 3 gives a briefoverview of how antennas and antenna arrays work. Chapter 4 provides a discussionFIGURE ... (DBS) systems have offered analternative to cable television, and the end of the Cold War has made many militarytechnologies available to civilian applications. The global positioning systems(GPSs),...

Tài liệu Lò vi sóng RF và hệ thống không dây P2 docx

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... axis.The Smith chart can be used to ®nd (1) GLfrom ZLand vice-versa; (2)ZinfromZLand vice-versa; (3) Z from Y and vice-versa; (4) the VSWR; and (5) dminanddmax. The Smith ... normalized values.2. Moving away from the load (i.e., toward the generator) corresponds tomoving in a clockwise direction.3. A complete revolution around the chart is made by moving a distancel ... degree ofaccuracy, by dividing P2by P1, ®nding the logarithm of the result, and multiplying itby 10.FIGURE 2.11 Transmission line connected to an open load.28REVIEW OF WAVES AND TRANSMISSION...

Tài liệu Lò vi sóng RF và hệ thống không dây P3 pptx

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... or microwave power.It is a reciprocal device, and the same antenna can serve as a receiving ortransmitting device. Antennas are structures that provide transitions betweenguided and free-space ... the HPBWand SLLs. Also shown is FNBW, the first-null beamwidth.3.5.5 Directivity, Gain, and EfficiencyThe directivity Dmaxis defined as the value of the directive gain in the direction of itsmaximum ... Þ¼12Re½~EE Â~HH*.The directivity of an isotropic antenna equals to 1 by definition, and that of otherantennas will be greater than 1. Thus, the directivity serves as a figure of meritrelating...

Tài liệu Lò vi sóng RF và hệ thống không dây P4 ppt

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... capacitances. Active ﬁlters can be builtby using active devices such as MESFETs in microwave frequencies and CMOS inRF. The active devices provide negative resistance and compensate for the losses ... biasing ﬁeld.Ferrite control devices are heavy, slow, and expensive. Solid-state control devices, onthe other hand, are small, fast, and inexpensive. The ferrite devices do have someadvantages ... thecomparison between ferrite and pi n diode control devices [1]. It should bementioned that the use of FETs or transistors as control devices could provide gaininstead of loss.Switches are widely...