RF-System Design

UHF Channel Emulator 868 MHz
An UHF channel emulator 868 MHz simulates the link between a reader and a RFID-tag. The channel attenuation and phase shift is implemented by cascading a vector modulator and a variable voltage controlled attenuator. Recorded test scenarios can be played reproducible and so be used for statistical analysis. In this way commercial UHF long range readers are tested under extreme conditions. For example the number of readouts can be determined. Furthermore the localization of successful readouts can be identified. Successful readouts occur in the minimum channel loss of the scenario which corresponds to the maximum received signal.

: Test results of a commercial reader in combination with the UHF channel emulator 868 MHz. Successful readouts occur in the minimum channel loss of the scenario which corresponds to the maximum received signal.

UHF channel measurements
The scenarios for the UHF channel emulator 868 MHz are measured by channel measurements. Therefore the following scenario is defined. The reader antenna is mounted in a height of 5.5m. The tag is mounted on a pallet and moved by a forklift along the driveway. The parameters for the channel measurement are the pivot angle of the reader antenna and the track displacement of the tag.

- UHF RFID reader 868/915 MHz with fully compliant EPC Class 1 Gen 2 standard
  - RF, analog and digital design
  - Complete baseband processing is done by FPGA
  - Configuration of all components is done by FPGA

DSRC channel emulator 5.8 GHz
A DSRC channel emulator 5.8 GHz was designed to simulate the RF link between the reader (TRX-Unit) and the On-Board-Unit (OBU). Therefore the communication between the reader and the OBU can be reproducible tested using dynamic scenarios. This is very important for characterizing and/or engineering readers or OBU�s. The reader is connected to the OBU via two anechoic chambers and the DSRC channel emulator 5.8 GHz. Neither the reader nor the OBU must be manipulated which makes the whole system very flexible.

Evaluation of grain angle, moisture content and density of spruce
The load bearing capacity of wood is strongly dependent on the grain angle, the moisture content and the density. The moisture content for example gives information of possible reduction gaps. It is very difficult to evaluate the grain angle without destruction and contacting the wood. The three parameters will be determined simultaneously by microwave measurement technology which is very important for the quality control of wood.
- Frequency: 8-12 GHz
- Linear polarized antennas
- Measuring the attenuation, phase shift and depolarization of the transmitted wave