Reinhold Herschel

Compact 3D imaging radar based on FMCW driven frequency-scanning antennas

In this paper the development of a wearable 3D FMCW radar sensor system for firefighters to enhance eyesight in smoky surroundings during hazardous situations is described. In order to obtain a real-time capable, small and lightweight sensor, two orthogonal oriented frequency-scanning meander-line antennas are combined with small broadband 57 GHz to 63 GHz FMCW radar-modules. This arrangement is used to scan both directions, azimuth and elevation, in a fast time-multiplexed mode. The gathered time-domain datasets for both scanning directions are transferred to 2D projections. A following data-processing step merges both of these orthogonal images into a 3D-image of the monitored area. As no mechanical parts are involved, this very simple 2 Channel radar concept is suitable for a high degree of miniaturization. Integration of the whole system into a wearable system deployable for a broad field of applications in security and defense seems to be feasible.

Miniaturized radar sensors supporting next generation UAVs

In this paper integrated radar modules are presented which are suitable for collision avoidance and imaging for small UAVs. A short introduction to electronic beam steering is given and different approaches for angle resolving imaging are shown. Two sensors, a mono-static 80 GHz radar sensor and a polarization resolving bistatic 94 GHz radar module are presented which can be valuable elements of sensor-suites for modern UAV based imaging and surveillance and autonomous operation.

Millimeter wave radar for high resolution 3D near field imaging for robotics and security scans

This paper presents different millimeter wave systems for robotic mapping and localization as well as for security scan applications. The 2D system in the first part of this paper is mechanically rotating the radar module to allow a continous revolving FMCW radar beam in azimuth plane. This extracted data is compared with the data of a LiDAR system. In the second part 3D imaging systems are presented based on synthetic aperture radar and MIMO arrays.

3D imaging system based on a MIMO approach at 360GHz for security screening

An active MIMO system at 360 GHz as a part of the EU FP7 project TeraSCREEN is presented. A combination of geometric focusing in elevation and MIMO based digital beam forming in azimuth will provide real-time 3D images. The MIMO system consists of 16 transmitter and 16 receiver antennas within one single array. This configuration represents a linear array of 256 virtual antennas. This set-up allows an azimuth resolution of 0.078 degrees. To achieve an elevation resolution of 0.15 degrees, the combination of a fast moving plane reflector and a focusing elliptical mirror is used. An FMCW-Radar bandwidth of 30 GHz results in a range resolution of 5 mm. With this system high resolution 3D images can be generated with 4 frames per second. The principle of the system is presented including the functional structure and the hardware design. This is followed by the description of the 30 GHz module, providing the analogue input signal for the submillimeter wave multiplier chain to achieve a Terahertz signal at 360 GHz.

Synthesis and design of narrowband bandpass filters in waveguide technique

The design and realisation of a high order bandpass filter for millimetre wave signals is presented. It is purely based on split-block hollow-metal waveguide technology. The synthesis process starting at the equivalent lowpass filter is demonstrated, involving the use of K-inverters and equivalent circuits for waveguide discontinuous. This results in a compact iris filter with less than 1.2GHz bandwidth at 94GHz and more than 40 dB suppression at 0.5 GHz offset while the insertion loss is kept as low as 3 dB. The design is verified by EM simulation and experimental characterisation of a manufactured prototype to underline the potential of the filter for innovative system design in the millimetre wave range.