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It is a common belief by many people that the resonant-cavity magnetron was invented in February 1940 by Randall and Boot from Birmingham University. In reality, this is not the full story. Rather, it is a point of view mostly advocated by the winners of the Second World War, who gained a great benefit from this microwave power tube (thanks to a tw...
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The German armaments production during World War II (1939-1945) is a highly debatable issue. Many studies point out that it was a success story since the overall production increased in spite of the heavy Allied air bombing campaign during the period 1943-1945. Others point out that the size of the production could not balance the aggregate product...
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... One of the main components of the radar is the transmitter that generates the EMW and travels through the duplexer in a monostatic radar [2]. The magnetron was invented and developed since the WWII associated the microwave radar systems to detect the objects (ships and aircrafts) [3]. The radar can be classified into two types with respect to the antenna location and power transmitter. ...
A magnetron is a power oscillator device used in several radar transmitters for generating the electromagnetic wave (EMW) with a constructive and fixed frequency. In this work, a radar transmitter has been carried out using magnetron operates at 2,458 MHz and two conducting layers waveguides to achieve minimum loss of the signal due to the increased temperature. The magnetron is connected with the high voltage capacitor (1.0 μF) in order to store the alternating current (AC) signal delivered from the high voltage transformer. A waveguide parts have been used as transmission lines in view of connecting the magnetron to the antenna. These parts include two metal layers, the upper layer (outer) is advanced audio coding (AAC) 1350 aluminum conductor and the lower (inner) is copper. The waveguide dimension should be suitable to flow frequency from 2.2 GHz to 3.3 GHz. To measure the operating frequency, a waveguide adapter and a coaxial cable which combined with n-female connector have been connected to magnetron. The wave is delivering to the frequency counter by Bayonet Neill–Concelman (BNC) to n-female connectors. The promising results of the proposed work have been achieved with a maximum power, efficient return loss, acceptable voltage standing wave ratio (VSWR) and low-cost manufacturing.
... Today, the physical effects of the high-power microwave are extensively employed in the military, communications, medical, food heating, and drying fields, and have become an essential component of scientific research and production life [1][2][3][4][5][6][7][8][9][10]. The magnetron is a potential vacuum electronic device; compared to other vacuum electronic devices, the utility model offers benefits such as small volume, inexpensive manufacturing cost, high market share, high power, and high efficiency, among others [11][12][13][14]. ...
As an essential vacuum electronic device for producing the microwave, the magnetron has various applications. This study developed a novel high-efficiency 12-vanes CW magnetron and anode resonance system that improved mode separation, expanded the working space of π-mode and made other modes more challenging to trigger, ultimately eliminating the possibility of mode jumping. A magnetron was simultaneously supplied with a particular quantity of anode voltage, and the cathode was generated by the electron, and high-frequency field interaction of a homogeneous magnetic field. The work efficiency of the 12-vanes CW magnetron was significantly enhanced. Given an anode voltage of 8000 V and a magnetic flux density of 3980 Gs as a consequence of particle simulation, the variation trend of a magnetron’s output power oscillation curve correlated with the development of hexagonal spokes. After a period of stable operation, the magnetron’s fundamental parameters were determined to be as follows: the primary frequency oscillation frequency was 2.466 GHz, the anode collision current was 1.08 A, the amplitude of sinusoidal oscillation was 125, the output power was 7812.5 W, and the corresponding power conversion efficiency was 90.42%. Changing the magnitude of the anode voltage or magnetic flux density resulted in a reduction in power conversion efficiency within a particular range; however, between 85% and 90% stability was maintained.
... Others did similar experiments. However, it was not until the availability of high-power sources, such as the cavity klystron and the improved six-cavity magnetron invented by Boot and Randall [1], that radar became a practical possibility. With relationships deteriorating in Europe and elsewhere, radar was envisaged as an important defense against aerial bombardment. ...
Advances in our understanding of the world around us are often stimulated by major technological achievements. A case in point was the development of radar. It led to huge steps in remote sensing practice and the creation of two science areas, namely remote interplanetary exploration and radio astronomy.
... It would be mass produced in the US mainly by Raytheon. Other groups also developed similar magnetron designs based on resonant cavities [20], the most notable being Alekseev and Malairov in Russia [21] who published a 4-cavity layout very similar to Boot and Randall's. By 1944, the Boot and Randall derived cavity magnetron had been scaled successfully to 3 cm (10 GHz) and the efficiencies and output power levels had been significantly improved with power levels at 10 cm reaching 2 MW and efficiencies near 50% [19]. ...
This article is the second in a continuing series of general interest papers on the applications of microwaves in areas of science and technology that might not be appreciated by the traditional engineer. What more appropriate application could there be than the first wide-spread commercial use of microwaves for food preparation. The development, use, and evolution (or lack of) of the microwave oven is the subject of this month's “Microwaves Are Everywhere.”
... The result was the FuMG 41/42 "Mammut" radar built in Germany in 1944 on the basis of an electronically steerable phased antenna array (PAA), which is supposed to be the world's first system of the kind [2]. However, PAAs have not become widespread at that time since with transition to higher sounding frequencies, after invention of the resonant-cavity magnetron [3], preference was given to simpler antenna systems with mechanical beam scanning like, for example, parabolic antennas [4,5]. ...
... Development of the cavity magnetron [1] took place in the early 20 th century, beginning with Gerdien [2] and Hull [3] in the 1910s, who described cylindrical, coaxial diodes with a magnetic field applied on the common axis. Variations ensued across the globe over decades, culminating with the work by Boot and Randall at Birmingham University in 1940 [4] when they introduced a cavity magnetron prototype with peak power of 15 kW at 3 GHz, well exceeding the goal of 1 kW at this wavelength. This invention was a disruptive breakthrough, enabling the detection of Axis air forces and submarines from more considerable distances. ...
... fdir = strcat(data_dir_temp,pow_fname); else filename = strcat(num2str(shot_num),'_002_00',... num2str(diode_ch_id(i)),'_Power',... num2str(diode_ch_id(i)),'.txt'); fdir = strcat(data_dir,filename); end %If the file exists, step in if exist(fdir,'file') == 2 pow_raw = csvread(fdir); if remove_signal_DC_offset == 1 dc_offset = mean(pow_raw(1:500,2)); pow_raw(:,2) = pow_raw(:,2) -dc_offset; end %movmean_npts = floor(size(sbo_pow_raw{j},1)/100); diode_data_input = (1E3)*abs(movmean(pow_raw(:,2),50)); pow = zeros(size(pow_raw,1),size(pow_raw,2)); pow(:,1) = pow_raw(:,1); pow(:,2) = Power_Calculation(diode_data_input,... diode_inputs(i,1),Total_attenuation(i,1)); left_col = strcat({'Output Power (MW),'}); print_metric(key_metric_path,char(left_col),max(pow(:,2))/1000) max_power_index = min( find( pow(:,2) == max(pow(:,2)) ) ); else error('invalid diode code. diode code can be (1,2,3,4) corresponding to (HM01, HM02, ML01, ML03)') end end %This function will accept an input NX1 vector and change the vector indices to %an appropriate value based on the shot number. Shot1 is the very first %shot in the series, shile first_shot is the first shot in the range and %last_shot is the last shot in the range. ...
Modern High Power Microwave (HPM) initiatives pursue challenges in fundamental science, such as fusion research and particle accelerators, as well as industrial applications and homeland security. RADAR, telecommunications, and counter-IED (improvised explosive device) measures also rely on HPM. Crossed-field devices, like the magnetron and magnetically insulated line oscillator (MILO), are a subclass of microwave sources capable of delivering HPM. This dissertation describes the theory, simulation, and design processes applied to produce novel contributions in two separate projects, one a relativistic magnetron and the other a MILO. The magnetron is an inherently narrowband source, which is undesirable for applications such as counter-IED technologies. Past Recirculating Planar Magnetron (RPM) concepts have proven multispectral microwave generation in magnetrons, and the Harmonic-RPM was designed to expand and further understand these capabilities. In the innovative configuration of this dissertation, the HRPM implements a 1 GHz, L-Band Oscillator (LBO) and a 2 GHz, S-Band Oscillator (SBO) on the same side of the planar cathode, both that are made frequency-agile by leveraging the novel phenomenon of harmonic frequency locking. An experimental investigation of harmonic frequency locking between the LBO and SBO demonstrated the LBO can be used to control the SBO frequency and phase through harmonic beam content, and the SBO responds to this excitation at varying degrees depending on its quality factor. In the low quality factor experiment, the HRPM was driven at 255 ± 19 kV, 1.23 ± 0.32 kA, producing microwave bursts up to 40 MW with shot-averaged pulse duration of 77 ± 17 ns at 7.3 ± 2.4% total efficiency. When the HRPM was properly tuned to excite the SBO on resonance in the low quality factor experiment, the shot-averaged SBO power was 28 ± 9 MW at 2.102 GHz ± 1.5 MHz. Harmonic frequency locking enabled tuning of the SBO over a range of 33 MHz in this experiment, corresponding to 1.6% tunability. By reversing electron rotation direction by the magnetic field, it was shown that the SBO was no longer influenced by the harmonic content of the LBO-modulated beam. The MILO is a variant of the magnetron, differentiating itself in its method of producing the magnetic field for synchronous interaction. The magnetron uses permanent magnets or pulsed solenoidal coils, whereas the MILO magnetic field is established by large, pulsed currents along the central axis of the device. The vast majority of MILO devices in the literature operate at a low impedance (V/I) of roughly 10 Ω and typically 50-60 kA, resulting in efficiencies commonly in the single digits of percent. The MILO investigated in this dissertation was the first to demonstrate oscillations at less than 10 kA currents, at -240 kV for an impedance of 25-30 Ω. Microwave bursts were observed up to 25 MW at 1.5% efficiency with shot-averaged frequency and pulse duration of 993 ± 7 MHz and 118 ± 43 ns, respectively. The shot-averaged output power was highly irreproducible at 10 ± 7 MW, and is significantly lower than simulation estimates. These experiments were compared with a contemporary theoretical treatment of Brillouin flow in the coaxial MILO geometry, which revealed consistent device operation in a unique condition near the Hull cutoff condition.
... The invention of the cavity magnetron in 1940 (through the Tizard Mission 2 ) and the subsequent development of radar and industrial applications are considered a "major innovation" according to the definition often used by technology historians. 3 Today, industrial cavity magnetrons abound and routinely operate reliably with beam-to-microwave conversion efficiencies exceeding 80%. The next big advance in the cavity magnetron was the relativistic magnetron, which was first investigated by Bekefi and Orzechowski at MIT in 1976. ...
The cavity magnetron is the most compact, efficient source of high-power
microwave (HPM) radiation. The imprint that the magnetron has had on the world
is comparable to the invention of the nuclear bomb. High- and low-power
magnetrons are used in many applications, such as radar systems, plasma
generation for semiconductor processing, and—the most
common—microwave ovens for personal and industrial use. Since the
invention of the magnetron in 1921 by Hull, scientists and engineers have
improved and optimized magnetron technology by altering the geometry, materials,
and operating conditions, as well as by identifying applications. A major step
in advancing magnetrons was the relativistic magnetron introduced by Bekefi and
Orzechowski at MIT (USA, 1976), followed by the invention of the relativistic
magnetron with diffraction output (MDO) by Kovalev and Fuks at the Institute of
Applied Physics (Soviet Union, 1977). The performance of relativistic magnetrons
did not advance significantly thereafter until researchers at the University of
Michigan and University of New Mexico (UNM) independently introduced new priming
techniques and new cathode topologies in the 2000s, and researchers in Japan
identified a flaw in the original Soviet MDO design. Recently, the efficiency of
the MDO has reached 92% with the introduction of a virtual cathode and magnetic
mirror, proposed by Fuks and Schamiloglu at UNM (2018). This article presents a
historical review of the progression of the magnetron from a device intended to
operate as a high-voltage switch controlled by the magnetic field that Hull
published in 1921, to the most compact and efficient HPM source in the
twenty-first century.
... The years of World War II brought rapid development of novel electronic devices; indeed, 1940 is claimed to be the year of the invention of the resonant-cavity magnetron by Randall and Boot from Birmingham University [5]. Even though the history of magnetron was different from the way it is presented by the winners of the World War II [6], this invention was unquestionably extremely important since it allowed for the construction of radars [7]. In 1943, Rudolf Kompfner introduced the traveling-wave tube (which was a great improvement over Haeff's similar device from pores microporous silica walls The material is inexpensive to synthesize and has numerous other advantages. ...
Electronics, and nanoelectronics in particular, represent one of the most promising branches of technology. The search for novel and more efficient materials seems to be natural here. Thus far, silicon-based devices have been monopolizing this domain. Indeed, it is justified since it allows for significant miniaturization of electronic elements by their densification in integrated circuits. Nevertheless, silicon has some restrictions. Since this material is applied in the bulk form, the miniaturization limit seems to be already reached. Moreover, smaller silicon-based elements (mainly processors) need much more energy and generate significantly more heat than their larger counterparts. In our opinion, the future belongs to nanostructured materials where a proper structure is obtained by means of bottom-up nanotechnology. A great example of a material utilizing nanostructuring is mesoporous silica, which, due to its outstanding properties, can find numerous applications in electronic devices. This focused review is devoted to the application of porous silica-based materials in electronics. We guide the reader through the development and most crucial findings of porous silica from its first synthesis in 1992 to the present. The article describes constant struggle of researchers to find better solutions to supercapacitors, lower the k value or redox-active hybrids while maintaining robust mechanical properties. Finally, the last section refers to ultra-modern applications of silica such as molecular artificial neural networks or super-dense magnetic memory storage.
... red copper -cores or anode blocks, green -long cathode, black -axial straps, stainless steel -outer shell. Each single core of the multi-core magnetron shown above mimics, to some extent, first multi-cavity magnetron built and tested just before the beginning of the WWii [72][73][74][75][76]. ...
The difference between frequency locking and phase locking of multi-cavity magnetrons (oscillators) is analyzed and the method of computer simulations of the locking phenomena in a virtually prototyped system of the coupled magnetrons operating within the same simulation domain is discussed. It is stated that while the frequency locking maybe demonstrated, if properly designed, by computer simulations of the coupled magnetrons operation during one simulation run only by showing an achievement of the same operating frequency of the simulated magnetrons, the evidence of the phase locking maybe demonstrated after at least two simulation runs by showing an achievement (in both simulation runs) of the same phase difference between simulated magnetrons already operating in the frequency-locked mode. The “phase difference” between magnetrons, θ, refers here and elsewhere below to the phase difference between induced electric field (magnetron) oscillations in the appropriate reference planes of the virtually prototyped system of the coupled magnetrons.
... As for France, it is known that two distinct approaches were explored very early [3,4]. The fi rst one resulted from advanced studies of the CSF company on the magnetron: the history of the fi rst centimetric radar, which equipped the liner Normandy in 1935 [5], was recently recalled in various papers [6,7]. Here, we will look at the second approach, initiated around 1925 by the French engineer Pierre David. ...
Abstract - Pierre David, a French pioneer of the 20’s in the VHF domain, is best known for his early work on Air Defense and detection of aircraft. His approach, which he called DEM (Electro-Magnetic Detection), was quite similar to the "beating method”, experienced at the same time at the American NRL, and which is recognized to have initiated the Radar concept in the US. Other developments, in Great Britain or more especially in Japan, are also discussed. But David is certainly the one who went furthest in field applications, to develop a French operational system which could meet the pressing threat of the nazi aviation. Results of the full-scale experiments of his “Electromagnetic Barriers” are described from test reports of the French Air Force unpublished to this day. A "Compagnie de Guet Electromagnétique" (Electromagnetic Warning Company) was then established to build up a Chain Home “à la française” along the German border. The outbreak of the war did not allow its deployment, apart from a limited facility in the Marseille region. But the principles that David had established to find an efficient solution for a true 3D localization (leading to the "Maille en Z" method) prefigured the modern approach of generalized multistatic sensors systems, which is popularized today under the MIMO (Multi Input Multi Output) concept.
