Proposal of a Handy Setup for Discriminating Parasitic Effects for the Measurement of Impulsive Thrust From a Microwave Cavity

Abstract

This paper details the work of the LAPLACE Electromagnetism Research Group to develop an original measuring setup dedicated to the detection of an EMDrive like force. Recent peer-reviewed experimental results [1, 2] were obtained using similar setups based on a torsion pendulum combined with an optical sensor. These very accurate measurement setups are appropriate for measuring such an extremely weak force. They also appear costly, which may discourage other research teams from working on this topic. Our main goal is then to provide an alternative configuration, based on a commercial precision balance, in order to build a measuring setup more affordable, handy, and accurate enough to measure an EMDrive like force. Our experimental system is capable of feeding a truncated cone shaped 2.45 GHz resonant cavity with power up to 140 W. To calibrate the EMDrive force and avoid false positive thrusts, an original setup has been proposed and evaluated. It allows us to really consider that the parasitic effects do not alter the hypothetical force measurement by the use of force direction switching during the measurement.

High Power Transmission Using Contactless Microwave Transition on an Emdrive Setup

“…Figure 8 exhibits the parasitic force (solid line) produced by thermal distortions of the coaxial cable structure as the generator provides 200 W RF power. Actually, considering the attenuations of each component of the feeding circuit, the RF power that passes through the coaxial cable can be estimated around 140 W. The cable therefore exerts an increasing tensile force on the system which causes the constant decrease of the overall weight as long as the microwave power passes through it (similar response to that of the previous paper [6]). Moreover, the curve steps are a good way to check the resolution of the balance, which is 10 mg (i.e., 0.1 mN).…”

“…In the operating frequency bandwidth (2.43-2.47 GHz), all accesses are well matched (less than −13 dB reflection), despite a frequency shift between simulations and measurements. Both transmission channels are very efficient (more than −0.4 dB transmission), and cross-talk levels are very low (below −40 dB), allowing us to easily implement the device in our shaker configuration [6].…”

“…In our previous measuring setup [6], the switch used to feed one or the other cavity is directly connected at their inputs. It is part of the Device Under Test (DUT) positioned on the balance and is connected by a single coaxial cable to the power feeder.…”

“…In our previous work [6], we developed an original test facility to measure an EMdrive like force. The chosen configuration, called shaker because of its shape, allowed to alternatively feed two cavities oriented in opposite directions without the intervention of an operator.…”

Straightforward Emdrive Setup Using a Microwave Contactless Transition: First Results on Frustum Cavities

“…This article is the third in our publishing approach detailing the advances of the setup. The first one focused on the development of this handy and affordable experimental setup [4]. It also revealed results obtained with a set of cavities in "Shaker" original self-calibrating configuration.…”