Introduction

 

             Microwave engineering is the part of communications engineering that is concerned with the transmission of the signal in the upper frequency range (above 1GHz). Frequency and Impedance Measurement experiment is one of the experiments of the microwave technology. In this Virtual Laboratory, there are 4 experiments will be discussed and converted to a software as the Virtual Laboratory of Frequency and Impedance Measurement experiment. The overview of these 4 experiments will be discussed below.

 

 

Experiment 1 : Frequency Measuring with Resonance Frequency Meter

 

 

The knowledge of frequency and wavelength is essential since most components and procedures in the microwave range demonstrate a frequency-dependent behaviour. The more components are used in a circuit and the longer the line used the stronger the frequency-dependent changes. Particular attention is due to the fact that the wavelength in air, l_o, depends on the frequency, f, and the propagation velocity, c, with the relationship: l_o = c / f

The wavelength in the waveguide (l_H) additionally depends on the dimensions of the waveguide and is longer than wavelength in air.

Nowadays, the frequency in the microwave range is often determined using microwave counters. This involves quite high equipment costs but the drawback is that it produces high accuracy. But if accuracy is less stringent, much cheaper resonant frequency meters can be used instead of counters. The resonant frequency meter diagram is shown in figure 2. The scaling of frequency meter and Oscillator data sheet will be referring in these experiments. Please refers the graph of this the scaling of frequency meter and Oscillator data sheet is at the appendix, figure 8 and figure 9.

 

      

        Figure 2: Resonant frequency meter