RU2567186C1 - Reflective delay line - Google Patents

Abstract

FIELD: physics, acoustics.

SUBSTANCE: invention relates to acoustoelectronic devices, particularly to reflective delay lines operating on surface acoustic waves. The technical result is achieved due to that the reflective delay line comprises a substrate made of piezoelectric material, on the surface of which there is an input transducer consisting of n interdigital transducers connected in parallel and lying on a common axis which is inclined at an angle α to the line of reflective elements arranged on both sides of the input transducer. The input transducer is placed such that the distances between the outermost interdigital transducers and the reflective elements, which define minimum (maximum) delay times, have different values, and reflective elements which generate the same pulse delay times of the information signal are in phase with each other.

EFFECT: high amplitude of the information signal and broader functional capabilities.

4 dwg

Description

The invention relates to acoustoelectronic devices, in particular to reflective delay lines (OLS), operating on surface acoustic waves (SAWs).

Known devices for generating an information signal operating on surface acoustic waves (SAWs) [1, 2]. Structurally, the devices contain a substrate of piezomaterial, on the surface of which an input transducer and reflective elements are made in the form of interdigital transducers (IDTs) arranged in sound channels.

The disadvantage of these devices is the insufficient amplitude of the pulses required to identify objects at large distances.

The closest in technical essence to the proposed technical solution is a multichannel SIR for surfactants, selected as a prototype [3].

A multichannel OLS (prototype) contains a substrate of piezoelectric material, on the surface of which an input transducer is made, consisting of n IDTs located on a common axis inclined at an angle α to the line of location of the reflective elements, the reflective elements being located on both sides of the input transducer and installed in one line.

The design of the OLZ prototype allows the formation of a multi-pulse information signal. However, due to the distribution of the energy of the acoustic wave generated by the input transducer along the sound channels, the pulse amplitudes of the information signal have a reduced value, because each pulse defines only one parameter, which limits the functionality of the OLS.

The technical result of the proposed design OLZ is to increase the amplitude of the information signal and the expansion of its functionality.

The technical result is achieved in that the OLZ contains a substrate of piezoelectric material, on the surface of which an input transducer is made, consisting of "n" IDT connected in parallel and located on a common axis, inclined at an angle a to the line of location of the reflective elements, which are installed on to both sides of the input converter. In this case, the input transducer is installed in such a way that the distances between the extreme IDTs of the transducer and the reflective elements that determine the minimum (maximum) time delays have equal values and, in addition, the reflective elements forming the same time delays of the information signal pulses are phased relative to each other .

In FIG. 1 shows the design of the proposed delayed optical delay, on which are indicated: 1 - a substrate of piezomaterial; 2 - input converter; 3 - IDT; 4 - reflective elements; 5, 6 - sensors for monitoring the parameters of the object. The distances from the extreme IDT 3 of the input transducer 2 to the reflective elements 4 are indicated by L. A, B, C, D, E, F, G, H - the length of the acoustic channels.

In FIG. 2 shows an information signal, in which 7-10 the pulses of the information signal with amplitude H _{1 are} indicated.

In FIG. 3 shows the information signal when the sensor 5 is triggered, the amplitude of the pulse 8 is designated H ₂ .

In FIG. 4 shows an information signal with triggered sensors 5, 6.

Structurally, the OLZ is made as follows: on the surface of the substrate 1 of the piezomaterial, an input transducer 2 is made, which consists of interconnected IDT 3 forming acoustic channels (shown by the dotted line in Fig. 1). On both sides of the input transducer 2 there are reflective elements 4 forming the same time delays, which are made phased relative to each other. The input Converter 2 is installed with a slope so that the distance between its extreme IDT 3 and the reflective elements 4 have equal values L. Sensors 5, 6 are connected to the reflective elements 4 to monitor the state of the object.

OLZ works as follows: when a short radio pulse is applied to the input converter 2, each IDT 3 excites an acoustic wave propagating from it in both directions (Fig. 1). Having reached the reflective elements 4, the wave is reflected and on the IDT 3 of the input transducer 2 forms response pulses 7-10 arranged in time and forming an information signal (Fig. 2).

The installation of the input transducer 2 at an angle to the reflective elements 4 with the condition for equal distances between the extreme IDT 3 and the reflective elements 4 divides the topology of the OLS into two parts that are identical to each other. Therefore, one part of the topology of the delay line contains acoustic channels with time delays equivalent to another part of the topology. Thus, the length of the acoustic channel A is equal to the length of channel H, the length of channel B is equal to the length of channel G, the length of channel C is equal to the length of channel F, the length of channel D is equal to the length of channel E. Since the reflective elements 4 are located on both sides of the input transducer 2, then its IDT 3 comes in two acoustic waves from reflective elements located in different parts, but having equal distances to IDT 3. Since the reflective elements 4 are phased, the signals coming from them to the input transducer are added (to Example pulses generated reflectors 4a and 4b). In this case, the input converter performs the function of an adder in which pulses with the same time delays are added up and form an information signal with an increased pulse amplitude.

The proposed OLZ can be used to generate an information signal in the system of remote identification and control of objects. Since this line provides approximately 2 times greater pulse amplitude in the information signal, compared with existing lines, its use will increase the range of identification of the object.

The second application of the proposed OLZ may be the control of the physical parameters of the object. To do this, to reflective elements located at the same distance from the input transducer 2, connect sensors, for example, temperature control within specified limits. When the first temperature limit value is reached, the sensor 5 is triggered, while the pulse amplitude decreases by 2 times (Fig. 3), when the second temperature limit value is reached, the sensor 6 is triggered, and the pulse amplitude will be logical zero (Fig. 4). Thus, with one pulse it is possible to fix two values of the controlled parameter, which extends the functionality of the proposed OLZ.

Thus, the technical task posed is to increase the range of identification of the object by increasing the amplitude of the pulses of the information signal and expanding the functional capabilities of the OLC solved.

Based on the above, the distinguishing features of the proposed OLZ from the prototype are:

- installation of the input transducer along a common axis, inclined at such an angle to the line of location of the reflective elements such that the distances between the extreme IDTs of the converter and the reflective elements that determine the minimum (maximum) time delays have equal values;

- reflective elements forming the same time delays of the pulses of the information signal are made phased relative to each other.

Literature

1. Patent RU 2158936 C2, 10.11.2000.

2. Patent RU 2486665 C1, 06.27.2013.

3. The decision to grant a patent for an invention, application No. 20112145915/08 (073734), the filing date of the application is 10/26/2012.

Claims (1)

A reflection delay line containing a piezoelectric substrate, on the surface of which an input transducer is made, consisting of n interdigital transducers (IDTs) located on a common axis that is inclined at an angle α to the location line of the reflective elements installed in the sound channels on both sides input transducer, characterized in that the input transducer is installed in such a way that the distances between the extreme IDTs of the transducer and the reflective elements that determine the minimum ( maximum) time delays have equal values, in addition, the reflective elements forming the same time delays of the pulses of the information signal are made phased relative to each other.

Images