Christoph Baer

A mmWave Measuring Procedure for Mass Flow Monitoring of Pneumatic Conveyed Bulk Materials

In this contribution a novel measuring concept for mass flow determination of pneumatic conveyed particles is presented. Therefore, the so-called pseudo transmission measurement concept was adapted for the simultaneous determination of volume fraction and particle flow velocity within a pneumatic conveying tube. The application of two ultra wideband 80-GHz FMCW radar systems increases the measuring accuracy and is used for measurements on a continuous particle flow. Therefore, an experimental pneumatic conveying system is introduced. Flow simulations of the conveying pipe and 3-D electromagnetic simulations of the measurement method illustrate the flow behavior inside the conveying tube and the RF-measuring performance, respectively. Measurement results concerning the volume fraction determination as well as the velocity determination will be presented and discussed in detail.

Improvements in distance measurement and SAR-imaging applications by using ultra-high resolution mm-wave FMCW radar systems

Due to advances in technology, resulting in coverage of even higher, and rarely used, frequency regions with low-cost semiconductors, ultra wideband radar systems are getting more feasible for several kinds of applications. In this contribution, the effects of using radar systems with an ultra high spatial resolution, in combination with high precision distance measurements, especially for solid bulk material, and short range synthetic aperture radar (SAR) imaging are discussed. Furthermore, measurements with a wideband (24.5GHz bandwidth) radar sensor in these applications have been done to demonstrate the advantages, of the high resolution. Especially distance measurement applications with many targets or disturbing scatterers benefit from the wide bandwidth. Here, for the measured scenario an accuracy enhancement of a factor 4 to 8 has been obtained by increasing the bandwidth from 4GHz to 24.5 GHz. Furthermore, short range SAR images with a nearly isotropic resolution of 1.3 cm in range, and 1.5 cm in azimuth direction (−6 dB width, Hanning window) are presented. The use of 24.5 GHz bandwidth, and the accordingly better range resolution, which is now in the same dimension as the azimuth resolution, drastically increases the image quality compared to images taken with 4 GHz bandwidth.

Contactless Detection of State Parameter Fluctuations of Gaseous Media Based on an mm-Wave FMCW Radar

In this contribution, we present an approach on the fluctuation detection of gaseous media concerning their state parameter, i.e., concentration, pressure, and temperature. Dielectric mixing equations that link the gas permittivity with the gas concentration and pressure are introduced and discussed. Furthermore, we prove the small temperature influence on the gas permittivity, because of the obvious temperature-pressure dependence of gaseous media. To verify the suggested gas permittivity theory, a pressure-resistant test container was constructed and built up. By means of a highly precise millimeter-wave radar system, we performed numerous test series on different gases for various investigations.

A planar orthomode transducer for broadband applications at 25 GHz using a stepped waveguide technique

In this contribution, a novel planar orthomode transducer is presented. It is based on a stepped waveguide technique that makes the transducer small and easy to handle. Several electromagnetic simulations were performed in order to optimize the transducers structure and to investigate possible production tolerances, respectively. The developed orthomode transducer was built up and measured in a back to back assembly. The broadband measurement results as well as its planar structure allow different kind of feeding which make the presented orthomode transducer suitable for numerous applications.

A multistatic feeding concept for beam steering based on a dielectric ellipsoidal antenna

A simple and easy to integrate concept for multi-static beam steering using an existing dielectric ellipsoidal lens antenna is presented in this paper. Good antenna characteristics allow a modification of the antenna for the desired beam steering for industrial applications at 24 GHz. Based on the so-called geometrical-optical lens approach and 3D-electromagnetic field simulations the concept is investigated and the resulting effects of the modification are depicted. The antenna beam can be steered within a range only limited by the antenna dimensions. Using multiple feeding elements in one antenna within the same plane, a multistatic beam steering can be realized. For the multistatic approach, the circular waveguides for the antenna feeding are limiting the achievable steering angles, due to the minimal distance between two waveguides. Measurements of a first prototype confirm the expected behaviour and demonstrate the applicability for industrial purposes. Hence, the concept is suitable for the realization of multiple beam angles using only one antenna for a chosen number of feeding points.

A broadband stacked patch antenna with enhanced antenna gain by an optimized ellipsoidal reflector for X-band applications

A broadband stacked patch antenna, based on an aperture coupled feeding with two patch elements is presented. The transmission line model is introduced as one possibility for the design of an aperture coupled antenna. 3D electromagnetic field simulations are used for optimization and allow a detailed investigation of the influence of the different antenna parameters on the return loss and the antenna gain. To minimize the effect of an undesired formed opposite side lobe of the antenna, resulting in a poor front-to-back ratio, an optimized ellipsoidal reflector is presented to focus the radiation in one main direction. A good return loss in a bandwidth of more than 4 GHz, i.e. 42 %, with a maximum antenna gain of 18.1 dBi is achieved. A first prototype verifies the simulation results and the functionality of the developed antenna design.

Contactless determination of gas concentration and pressure based on a low jitter mmWave FMCW radar

In this contribution a novel approach on the determination of gas concentration and pressure is presented. Dielectric mixing equations are shown that explain the relation of permittivity and gas concentration. By means of the mixing equations edge case, an approximation for dielectric behavior of pure gas pressures is affiliated. A test container and a highly precise mmWave radar system enable the establishment of a fast and precise time domain measurement, named pseudo transmission measurement, for gas measuring tasks. Measurements that were performed on the test setup prove the suggested dielectric gas-theory and are discussed in detail.

A millimeter-wave based measuring method for the differentiation of atherosclerotic plaques

In this contribution, a novel measuring method for the differentiation of intra vascular plaque types is presented. The proposed method operates contact free because of the mm-wave based approach. Fundamentals concerning material properties of blood and plaque, and electromagnetic barrier reflections are discussed. Furthermore, a test setup consisting of a miniaturized sensor setup is introduced that clarifies the measuring concept. Additionally, results of 3D electromagnetic field simulations as well as first measurements ex situ performed on non-human genetic materials are shown and discussed in detail.

A monostatic antenna-reflector system for ultra-short-range radar applications

In this contribution, a novel antenna-reflector system is introduced, which consists of a planar waveguide orthomode transducer, a lens-horn antenna and a transpolarizing reflector. The proposed antenna system eliminates short-range clutter effects like root point reflections and antenna ringing effectively. The setup enables ultra-short-range radar measurements as they are used e.g. for material characterization measurements. Results of 3D-electromagnetic field simulations as well as measurements, that prove the effectiveness of the antenna setup are shown and discussed in detail.

Pseudo transmission measurement concept for the volume fraction determination of rice in a pneumatic conveying system

In this contribution, a measurement concept for the volume fraction determination of pneumatic conveyed rice, named pseudo transmission measurement, is presented. The theoretical background of the pseudo transmission measurement as well as an adequate permittivity mixing equation is discussed in detail. Due to the essential knowledge of the rices permittivity for the mixing equation, a waveguide cut-off frequency measurement for bulked materials is introduced. Because the pseudo transmission measurement is based on a cross polarization effect, a transpolarizing reflector is introduced and simulation results are presented. Additionally the pseudo transmission measurement is performed and evaluated on various amounts of dispersed rice inside a borosilicate glass tube.