Exclusionary pricing in two-sided markets

This paper studies the incentives to engage in exclusionary pricing in the context of two-sided markets. Platforms are horizontally differentiated, and seek to attract users of two groups who single-home and enjoy indirect network externalities from the size of the opposite user group active on the same platform. The entrant incurs a fixed cost of entry, and the incumbent can commit to its prices before the entry decision is taken. The incumbent has thus the option to either accommodate entry, or to exclude entry and enjoy monopolistic profits, albeit under the constraint that its price must be low enough to not leave any room for an entrant to cover its fixed cost of entry. We find that, in the spirit of the literature on limit pricing, under certain circumstances even platforms find it profitable to exclude entrants if the fixed entry cost lies above a certain threshold. By studying the properties of the threshold, we show that the stronger the network externality, the lower the thresholds for which incumbent platforms find it profitable to exclude. We also find that entry deterrence is more likely to harm consumers the weaker are network externalities, and the more differentiated are the two platforms

Virtual prototype of innovative ka-band power amplifier based on waveguide polarizer

This paper outlines an innovative approach to design a spatial power-combining structure based on waveguide polarizers. It presents the 3D CAD model of the new structure with the transversal probes and considerations in positioning and optimization of them. Exploiting the transformation of the dominant input mode TE10 into an elliptically polarized wave, provided by the polarizer, it has been possible to achieve a division of power by eight, completely carried out in space. With the insertion of the transversal probes made by microstrips, the RF signal can be sent to the MMIC solid state power amplifiers, and then recombined in the output section. Thanks to the large number of power divisions made in the waveguide section, the insertion loss of the power divider/combiner is less than 0.5 dB across the 32-34 GHz band, achieving a great power density as well. At the authors’ best knowledge, this is the first work where a waveguide polarizer is used in Spatial Power Combining technology

Innovative Mode Enhancement for High Power Coaxial Vircators

The size and weight of a high power microwave (HPM) source can make a difference in strategic use. The compactness of the virtual cathode oscillator (vircator) is undoubtedly the most significant advantage of this device. Civil industry and agriculture can use it to treat objects, food, and soils for disinfestation and disinfection. Vircators could also generate electromagnetic pulses (EMPs) to force the arrest of vehicles and drones; EMPs could inhibit or activate improvised explosive devices (IEDs). The coaxial type vircator is a highly compact device. Due to its symmetric geometry, coaxial vircator is typically designed to work with a TM01 mode. Still, when radiated into space, this mode gives maximum RF energy away from the antenna axis, a situation not desired. Instead, the TE11 is convenient in applications involving precise antenna pointing since this mode gives a maximum RF energy precisely aligned to the antenna axis. By studying Mathieu functions applied to elliptical waveguides, we improve the performances of a TE11 mode coaxial vircator using an elliptic drift tube (EDT). This is a completely innovative solution to reduce the mode competition inside the coaxial vircator. The rms and peak output power efficiency of the EDT coaxial vircator were measured on the TE11 mode, obtaining the values of 6.1% and 10%, respectively, with a peak power of 450 MW in a highly compact device

A New Theoretical Approach of Studying Resonances in Single Finline Transitions

In this article an innovative method of studying and removing the resonances, inherently exhibit by some waveguide to microstrip transitions, is presented. By modeling an equivalent circuit, this new approach allows to obtain the constructive parameters of a finline to microstrip transition, only using the values of the resistance and capacitance components of the equivalent circuit. This procedure will allow small microwave design Companies to realize these transitions only implementing circuit analysis software, and not having to afford electromagnetic analysis software, which are very expensive and time-consuming. A full 3D electromagnetic analysis confirms that the simulation results are in excellent agreement with the results obtained by the new equations discussed in this work

An Innovative Odd-Power Divider by means of a Triple FinLine Waveguide to Microstrip Transition

This paper outlines a novel approach to design a waveguide to microstrip finline transition that allows a division by three, of the RF power traveling inside a rectangular waveguide. The possibility of obtaining an odd power division of microwave and millimeter-wave signals with such finline transition is completely unexplored yet a harbinger of great opportunities. Starting from a 3D CAD model of the structure and continuing with electromagnetic simulations, the obtained results completely describe a transition able to achieve an almost perfect power splitting by three. Multyphisics simulations show an intrinsic resistance to vibrations of such transition, allowing it to be installed on aircraft or satellites modules. Thanks to this achievement, a totally new kind of power devices will come next, exploiting this odd power division. In fact, it will be possible to realize different types of microwave amplifiers, increasing the efficiency and decreasing the occupied size. To the author’s best knowledge, it is the first time a divider by three finline transition is reported in the literature

Electron Gun and Magnetic Systems Studies for a 36 GHz Klystron Amplifier

Self consistent analytic and numeric design for a set of innovative electron guns suitable for Ka-band klystrons is proposed in this paper. The proposed electron sources are designed to produces narrow beam with high currents that can be used in devices with critical dimensions. The proposed set of electron gun is destined to high power klystrons to be used as power sources for accelerating structures operating in Ka-Band. This family of accelerators is foreseen to achieve energy gradients around 150 MV/m. A klystron amplifier is being investigated in order to feed a linearizer structure. In this paper different electron gun and beam focusing channel designs are presented

Multiphysics Design of High-Power Microwave Vacuum Window

This paper presents the Multiphysics Analysis of a High- Power Microwave Window for a Ka-Band Klystron providing 16MW of peak power. After the optimization of the electromagnetic performances, we analyze the effect of RF heating effect and the stress of the pressure on the window. We also analyze the multipactor effect, that is a common cause of window failure. Using such approach, it is possible to realize a virtual prototype capable to represent in a complete way the real prototype to be manufactured

Efficiency Enhancement for an S-Band Axial Vircator Using 5-Stage Two-Step Tapered Radiators

An S-band multistage axial virtual cathode oscillator with efficiency enhancement for high pulsed power electromagnetic applications is presented. The Particle-in-Cell (PIC) results of the designed 5-stage Vircator, with two-step negative tapering in the reflectors, carried out by CST Studio suite 2021 simulation code show a peak power value of 5.54 GW and an efficiency value of 13.65% at 2.45 GHz, under a beam voltage and current equal to 520 kV and 20 kA, respectively

Studies of a Ka-band high power klystron amplifier at INFN-LNF

In the framework of the Compact Light XLS project [1], a Ka-band linearizer with electric field ranging from 100 to 150 MV/m is requested [2, 3, 4]. In order to feed this structure, a proper Ka-band high power klystron amplifier with a high efficiency is needed. This paper reports a possible solution for a klystron amplifier operating on the TM010 mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 44% and 10.6MW radiofrequency output power. We discuss also here the high-power DC gun with the related magnetic focusing system, the RF beam dynamics and finally the multiphysics analysis of a high- power microwave window for a Ka-band klystron providing 16 MW of peak power