Surface Acoustic Wave Device
Figure 1: SAW- device width linear decreased spacing of the transducers
Figure 1: SAW- device width linear decreased spacing of the transducers
Figure 1: SAW- device width linear decreased spacing of the transducers
Surface Acoustic Wave Device
SAW (Surface Acoustic Wave) filter is a piezoelectric component. It is a part of analog signal processing as a resonant component.
Compared to pure resonance components in electronics, the SAW filter in radars has the additional function of a frequency-dependent delay. SAW filters are used in radar systems with analogue intrapulse modulation and pulse compression and pulse compression and expand or compress a broadband signal.
A broadband transducer is vapor-deposited on a piezo crystal, which converts the electrical oscillations into mechanical oscillations in the crystal. However, these mechanical oscillations propagate at a much lower speed than the electrical signals on a line. Therefore, relatively high delay times are achieved. Frequency-dependent transducers are also vapor-deposited on the same crystal, which converts the mechanical energy on the crystals surface into electrical signals.
Due to the inevitably different distance of these transducers to the excitation system, the different frequency components of the input signal get a different time delay so that all frequency components of the input signal are pushed into the same rangecell and are superimposed to a short, sharp output pulse.
However, the summation of the different partial frequencies inevitably produces, in addition to the sharp output pulse, disruptive side lobes, so-called time sidelobes, which often have to be compensated for by complex procedures.
The same filter used for pulse compression in the receiver is used in the waveform generation in a reverse signal flow direction to achieve an optimum response of the SAW filter in the receiver.