Crossedfield amplifiers cfa share several characteristics with magnetrons. Gan solid state power amplifiers, solid state power. Crossedfield amplifiers, crossedfield amplifiers cfas. Browns work to adapt magnetron principles to create a new broadband amplifier is generally recognized as the first cfa, which he called an amplitron. He joined raytheon in 1940 and began work on their. Download microwave devices and circuits by samuel y. Other articles where crossedfield amplifier is discussed.
Crossed field amplifier tubes number of amendments. Peak and average power levels achieved were approximately one uegawatt and 20 kilowatts, respectively. A power oscillator such as a magnetron also can be used as the transmitter. The crossed field amplifier cfa is a boise state university research project. For a zipped copy of the hatelykabbary crossed field antenna patent in tif format, click here. The recirculating planar crossedfield amplifier rpcfa was designed and simulated using the finiteelement frequencydomain code. On the crossed field antenna performance, part 1 reprinted from 56th ieee bts transactions, sep 2006 dorado and trainotti. L3harris electron devices is the world leader in crossed field amplifier cfa production and development, delivering devices from l to xband, with power levels from 60 kw to 5 mw peak. Both contain a cylindrical cathode coaxial with an rf structure, and each of these tubes constitutes a diode in which a magnetic field is established perpendicular to an electric field between the cathode and the. Gain was nominally 30 db at efficiencies as high as 807. Methods of measurement of electrical characteristics of microwave tubes, part 10. In the receiver for first stages usually a diode mixer is used.
Crossed field amplifier emitter control eeweb community. Cfa has a noisier output than either a klystron amplifier or twt. The computations show that gains as high as 15 db with efficiencies in the range of 50 to 70 percent can be attained. L3harris cfas are currently being produced for some of the worlds most advanced radar systems such as the aegis anspy1 and the. In the early designs the discharge became erratic below 10 3 pa, and was often extinguished completely at 10 4 pa. The emitter current is controlled by setting the gate voltage to a value than the emitter voltage. Broadband crossedfield amplifiers cfas, based on electron flow in. He then focuses on microwave vacuum electronics, explaining the physics and theory of the interaction of electron beams with electromagnetic fields in quasistationary systems such as diodes and klystrons, systems with continuous interactions such as traveling wave tubes, backward magnetrons and crossed field amplifiers, and systems based on stimulated radiation of classical electron oscillations. Janfeb, 47 on the crossed field antenna performance, part 2 dorado and trainotti. What is the abbreviation for crossed field amplifier.
Generally, an amplifier or simply amp, is any device that changes, usually increases, the amplitude of a signal. L3harris cfas are currently being produced for some of the worlds most advanced radar systems such as the aegis anspy1 and the patriot missile system. Cpi bmds crossedfield amplifiers cfas are broadband. The configuration of a typical presentday distributed emission amplifier is similar to that of the magnetron except that the device has an input for the introduction of rf energy into the circuit. It is a twoport electronic circuit that uses electric power from a power supply to increase the amplitude of a signal applied to its input terminals, producing a proportionally greater amplitude signal at its output. This is the multiple choice questions in chapter 11. Traveling wave tube having transverse magnetic and electrostatic fields. Price university of connecticut summary electronic interaction in an injected beam forwardwave amplifier was analyzed by simulation in a digital computer. A crossed field amplifier cfa is a specialized vacuum tube, first introduced in the mid1950s and frequently used as a microwave amplifier in veryhighpower transmitters. Principles of klystrons, traveling wave tubes, magnetrons. Subset of the cycloidal electron paths into a crossedfield amplifier. The first is to demonstrate the feasibility of an rf turnon, rf turnoff, reentrant stream crossed field amplifier. One of the first crossedfield tubes used in early radars was the magnetron, and it was the only one available for quite a few years.
An amplifier, electronic amplifier or informally amp is an electronic device that can increase the power of a signal a timevarying voltage or current. An experimental vehicle built to verify the design was not successful because of. Preliminary results of calculations for the different. Crossed field amplifier combat information center combat systems evaluation laboratory electronic countermeasures engineering development model extended range electronic warfare support measures fleet command centers gru gsel mti nccs nrl ntds opeval p31.
I am currently a research assistant ra on this project. Maharashtra state board of technical education autonomous. In magnetron, continuous interaction between rf field and beam of electrons take place over the entire length. A crossed field amplifier cfa is a specialized vacuum tube, first introduced in the mid1950s and frequently used as a microwave amplifier in veryhighpower transmitters raytheon engineer william c. The continuouscathode emittingsole crossedfield amplifier. This is a large file, 242 mb in size, but it is a high resolution color scan and well worth the download. The discharge is generally not stable in crossed field gauges. Media in category crossedfield amplifier the following 4 files are in this category, out of 4 total. A crossedfield amplifier cfa is a specialized vacuum tube, first introduced in the mid1950s. Cfa abbreviation stands for crossed field amplifier. Abstract the design of an sband axial injection crossedfield amplifier capable of 5 kw cw and x db of gain is described.
Crossedfield tubes crossedfield tubes get their name from the fact that the dc electric field and the magnetic field are crossed at right angles. Crossed field amplifiers how is crossed field amplifiers. The recirculating planar crossedfield amplifier rpcfa is an adaptation of the recirculating. Highpower recirculating planar crossedfield amplifier design. Crossed field amplifier internal operation the electric and magnetic fields in a cfa are perpendicular to each other crossed fields. What links here related changes upload file special pages permanent link page. Otherwise, the tube would present an open circuit to the modulator, resulting in a. This is the same type of field interaction used in a magnetron.
How to establish a bias point bias is the state of the system when there is no signal. Quarterly progress report study of crossed field amplifiers 15 september 1965 da 36039 amc02164e this report presents progress on research in crossed field amplifiers for the quarter ending 15 september 1965. A data reduction process was then employed to characterize the radar system performance, which in essence validated the parallel amplifier concept of the spyia transmitter. The electric and magnetic fields in a cfa are perpendicular to each other crossed fields.
A crossedfield amplifier cfa is a specialized vacuum tube, first introduced in the mid1950s and frequently used as a microwave amplifier in veryhighpower transmitters raytheon engineer william c. A crossedfield amplifier using a distributed field. The relationship of the input to the output of an amplifierusually expressed as a function of the input frequencyis called the transfer function of the amplifier, and the magnitude of the transfer function is termed the gain. In electronics, a vacuum tube, an electron tube, or valve or, colloquially, a tube, is a device that controls electric current flow in a high vacuum between electrodes. Magnetron vs crossed field amplifierdifference between.
Crossed field amplifiers have very good efficienciesup to 80%, but the gain is limited. Oct 01, 2014 340 microwave linearbeam tubes 0 type chap. Experimental cathodedriven circuitonemittingsole crossed field amplifiers have been designed and built at sband under a navy program contract no. However, a magnetron is an oscillator and a cfa is an amplifier although a cfa can be.
A forwardwave, beamtype microwave amplifier that uses crossed field interaction to achieve good phase stability, high efficiency, high gain, and wide. High power amplifier tubes klystron traveling wave tube crossed field amplifier voltage 1 mw requires 90kv 1 mw requires 90kv 1 mw requires 40kv gain 30 70 db 30 70 db 8 30 db bandwidth 1 8 % 10 35 % 10 15 % xrays severe, but lead is reliable severe, but lead is reliable not a problem efficiency basic 15 30 % 15 30 % 35 45 %. Principles of klystrons, traveling wave tubes, magnetrons, cross field ampliers, and gyrotrons a s gilmour download bok. Crossedfield amplifiers chapter 16 microwave and rf vacuum. Description of the function of a crossedfield amplifier tube cfa or amplitron. Jan 22, 2016 crossed field amplifier a crossed field amplifier cfa is a specialized vacuum tube, first introduced in the mid1950s and frequently used as a microwave amplifier in veryhighpower transmitters. The design of this stage takes skill and care as explained in my earlier paper. Browns work to adapt magnetron principles to create a new broadband amplifier is generally recognized as the first cfa, which he. Marapr, 35 program your own voice keyer recorder gradijan. An electron, a current carrying wire, or a magnet can produce a magnetic field. The cfa is similar in operation to the magnetron and is capable of providing relatively large amounts of power with high efficiency.
Pdf a high power crossfield amplifier cfa is under development at slac to provide sufficient peak power to feed a section of an xband accelerator. Magnetic amplifiers for voltage regulation applications. Brown received his bsee from iowa state university in 1937, and his msee from the massachusetts institute of technology in 1941. Cfa cross field amplifiers linked to trusted tde listed vendors. The design of an sband axial injection crossed field amplifier capable of 5 kw cw and x db of gain is described. Crossed field amplifiers have another advantage when used as the final stages of a transmitter. To read and print pdf files, download adobe acrobat reader. Download fulltext pdf download fulltext pdf download fulltext pdf fea crossedfield microwave amplifier conference paper pdf available august 1993 with 85 reads.
Magnetic materials are described by the magnetic field that is created when a current flows through a magnetic material and the magnetic flux density. Brown may 22, 1916 february 3, 1999 was an american electrical engineer who helped to invent the crossed field amplifier in the 1950s and also pioneered microwave power transmission in the 1960s brown received his bsee from iowa state university in 1937, and his msee from the massachusetts institute of technology in 1941. Several varieties exist including the forwardwave backwardwave types, and the injectedbeam continuouscathode emittingsole. A crossedfield amplifier cfa is a specialized vacuum tube, first introduced in the mid1950s and frequently used as a microwave amplifier in veryhighpower transmitters. When no pulse is present, the tube acts as a section of. The crossed field amplifier amplitron the crossed field amplifier cfa, commonly known as an amplitron and sometimes referred to as a platinotron, is a broadband microwave amplifier that can also be used as an oscillator. This third edition has been extensively revised to better reflect modern advances.
During this period it was planned to modify the cathode design in the crossed field. Pulse modulated magnetrons, klystrons, and travelling wave tubes twt or crossed field amplifier cfa are used as transmitter output tubes. Different types of microwave tubes amplifier wireless. Also other names are sometimes used for the crossedfield amplifier in the literature. Recirculating planar crossedfield amplifiers deep blue. Purchase crossedfield microwave devices v2 1st edition. Absfractthe crossedfield amplifier cfa is an outgrowth of. Power amplifier transmitter using crossed field amplifiers. Brown may 22, 1916 february 3, 1999 was an american electrical engineer who helped to invent the crossedfield amplifier in the 1950s and also pioneered microwave power transmission in the 1960s. In crossed field amplifier, rf field remains stationary. Pdf a high power crossfield amplifier at xband researchgate.
An easily constructed highquality singleended 8w amplifier. In the past, major stress has been placed upon the important problem of noise iden. The crossedfield amplifier amplitron the crossed field amplifier cfa, commonly known as an amplitron and sometimes referred to as a platinotron, is a broadband microwave amplifier that can also be used as an oscillator. Cpi bmds crossedfield amplifiers cfas are broadband, phasestable microwave amplifiers used in coherent radar chains to efficiently generate very high peak output powers from relatively low input voltages which can be either applied to the cathode or an electrode similar to a twts cathode or grid pulsing, and in relatively small. Crossed field amplifiers cfa share several characteristics with magnetrons. Cpi bmds crossedfield amplifiers cfas are broadband, phasestable. The crossedfield amplifier amplitron the crossedfield amplifier cfa, commonly known as an amplitron and sometimes referred to as a platinotron, is a broadband microwave amplifier that can also be used as an oscillator. Skowron invited paper absfractthe crossed field amplifier cfa is an outgrowth of the magnetron.
The phasesplitter is a very critical part of the pp amplifier, and its behaviour is of great importance for the performance of the amplifier. Legally binding document step out from the old to the newjawaharlal nehru invent a new india using knowledge. Gyratron crossed field tube which can be used as an amplifier or an oscillator. The magnetic field is denoted h and has the units am, the magnetic flux density is defined as b with the units tesla. Media in category crossed field amplifier the following 4 files are in this category, out of 4 total. Apl contributions to aegis applied physics laboratory. The rf dynamic range of the cfa is enhanced by proper design of a reflector electrode at the sides of the interaction space. Find out information about crossed field amplifier. Typically, the first stage and the second stage are travelingwave tubes twt and the final stage is a crossed field amplifier. Klystrons, traveling wave tubes, magnetrons, crossedfield.
Crossedfield amplifier,crossedfield amplifier inventors. For a zipped copy of the henf crossed field antenna patent in tif format, click here. Request pdf a crossedfield amplifier using a distributed field emission cathode we propose to use an addressable array of emitters to provide a distributed electron source for use in a. Microwave tubes and circuits from the book electronic communication systems by george kennedy. Pdf fea crossedfield microwave amplifier researchgate. When no pulse is present, the tube acts as a section of waveguide. The crossed field amplifier cfa, is a broadband microwave amplifier that can also be used as an oscillator stabilotron. At microwave frequencies, however, the transit time or angle is large compared to the period of the microwave signal, and the potential between the cathode and the. Figure 1 illustrates the key operational features and test capabilities of the coherency test set. Liao an ideal text and a ready reference on the latest in microwave electronic technology, this book provides a unified presentation of microwave solidstate devices, microwave tubes and microwave circuits. The amplifiers in this type of power amplifier transmitter must be broadband microwave amplifiers that amplify the input signals without frequency distortion.
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