2.1. Experimental Setups

2.2. Laboratory Sessions

4.

Signal mixing and filtering; Analysis of the use of the combination of a mixer and a LPF in FMCW radar systems is performed in this lab session. By repeating the procedures in Experiment 2, an IF signal is obtained at the mixer output. The presence of harmonics beyond the desired wideband down-converted signal (270-783 MHz) is interpreted. On the other hand, the output of the mixer is connected to LPF. Results are compared using SA to understand the effect of the LPF.

5.

Antennas, connectors, and cabling; Basic concepts regarding antenna gain and connectors/cabling loss are covered in this lab session, as well as analysis of the radio link in terms of link budget. The experimental setup of this experiment is given in Figure 4.

In this experiment, the received signal power is going to be recorded from the SA for different separation distances between the two antennas, as well as for different frequency bands. Finally, the theoretical values of the received signal power are compared with the experimental values. The difference margins between the theoretical and experimental results are discussed and analyzed.

6.

Modular transmitter design; The modular transmitter design used for the FMCW radar system is explained in this lab session. Furthermore, the experimental analysis regarding determining the radar range is performed. Using the recorded received signal on the SA at different distances, the link budget equation is written and all the losses (cable, connectors, channel, etc.) are estimated. The bandwidth of the FMCW signal is determined such that the range resolution is 30 cm. The range resolution formula is given as $d_{res}={\displaystyle \raisebox{1ex}{$c$}\!\left/ \!\raisebox{-1ex}{$2B$}\right.}$ where B is the bandwidth of the signal and, c is the speed of the light. The maximum distance between the Tx and Rx has been estimated such that the peak power to noise power level is higher than 25 dB.

7.

Modular receiver design; The modular receiver design used for the FMCW radar system is given in this lab session. Additionally, determining the RCS of a reflector plate is measured by performing an experimental demonstration to the students. The experimental setup is given in Figure 5.

The FMCW radar used in this experiment is a monostatic radar system. In this experiment, the received signal power is recorded from the SA for different separation distances between the radar and the target. Using the radar range equation formula given in (1), the RCS (σ) of the target at every distance of observation is estimated.

$$R_{max}={\left({\displaystyle \frac{P_t{G}^2{\lambda }^2\sigma }{\left({4\pi }^3\right)S_{min}}}\right)}^{{\displaystyle \frac{1}{4}}}$$

(1)

where $R_{max}$ refers to the distance that the received power is measured at, $S_{min}$ is the recorded received power from the SA, $P_t$ is the transmitted power, $G$ is the gain of each antenna, and λ is the wavelength at the desired frequency.

8.

Modular radar design: This lab session focuses on explaining the complete modular FMCW radar design given in Figure 1, as well as performing several experimental analyses for determining the range of targets. The target used in the monostatic radar system is a metallic plate (reflector plate) to be placed at four different ranges. The measurement of the beat frequency, $f_b={\displaystyle \raisebox{1ex}{$4BR$}\!\left/ \!\raisebox{-1ex}{$c{T}_m$}\right.}$ which gives the range information is recorded from the SA and is compared with the theoretical value. Also, the presence of frequency offset due to the cables and connectors is discussed. In the later equation, $B$ is the modulation bandwidth and $T_m$ is the period of triangular signal (modulation period) [29].

9.

Introduction to TI mmWave Radar Platform; Understanding of the TI mmWave radar platform [30], its hardware components, and the radar parameters that affect the practical RCS measurement of a target are discussed in this lab session. The combination of the AWR1642 radar module and the DCA1000 data capture is used. The platform transmits an FMCW signal via two transmitters and it receives back the echoed signal via four separate receiving channels. The received signal is presented in the form of complex I/Q at Intermediate Frequency (IF) band. The signal is transferred to a computer and the processed data is acquired using the mmWave studio program. The settings and calculations of the radar parameters and their association with each other are discussed, and the measurement of the target RCS is performed.

10.

TI mmWave radar platform; Understanding the configuration parameters of an FMCW radar according to the maximum range, best range resolution scenarios, and RCS measurements of different objects are demonstrated in this session. With the calculation of the chirp signal parameters, several experiments based on different scenarios are conducted. Measurements of targets at different distances are conducted considering the maximum range equation given in (3) and the measurement of the range resolution is also performed to see the ability of distinguishing two objects close to each other.

$$d_{max}={\displaystyle \frac{c*f_{AD{C}_{sampling}}}{2*S}}$$

(2)

where $f_{AD{C}_{sampling}}$is the Analog Digital Converter (ADC) sampling frequency and $S$ is the slope of the transmitted chirp. Finally, the relationship between the maximum range and the range resolution is considered based on the theoretical formulas.

2.3. Assessment Methods

3.1. Interviews

3.2. Anonymous Surveys

3.3. Laboratory Quizzes