Trade-Offs for Wireless Transcutaneous RF Communication in Biotelemetric Applications

Pitz, Inke; Hall, Leonard; Hansen, Hedley J.; Varadan, Vijay K.; Bertram, Christopher; Maddocks, S.; Enderling, S.; Saint, David A.; Al-Sarawi, Said F.; Abbott, Derek

doi:10.1117/12.476427

Cited by 5 publications

(7 citation statements)

References 13 publications

(14 reference statements)

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“…Consists of piezoelectric substrate, an input IDT and an output IDT. 3 As it was mentioned above, the key novelty in this proposed microvalve structure is the use of a SAW device as a power transferring mechanism for the microvalve actuation, while operating as a wireless and secure interrogation unit. Hence there is no requirement of a battery and a number of issues related to attaching a battery with an implantable device can be simply ignored.…”

Section: Saw Devicesmentioning

confidence: 99%

“…Based on the published literature, it can be noted that SAW devices are mainly used for wireless communication, sensing and interrogation applications. [1][2][3] However SAW devices also being used to develop fluid transfer microsystems such as flexural micropumps and micromachines such as ultrasonic micromotors, micromirrors etc. 4,5 The fabrication of SAW devices is also becoming easier, especially with microfabrication technologies such as photolithography and X-ray lithography in combination of other well-known processes.…”

Section: Introductionmentioning

confidence: 99%

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Surface acoustic wave device based wireless passive microvalve for microfluidic applications

Dissanayake

Al-Sarawi

Abbott

2007

BioMEMS and Nanotechnology III

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There are vast advantages in the realisation of a SAW device based microvalve in Micro Electro Mechanical Systems (MEMS) and Nano Electro Mechanical Systems (NEMS) such as secure, reliable and low power operation, small size, simplicity in construction and cost effectiveness. In this paper, a Surface Acoustic Wave (SAW) based microvalve that generates micro actuations for microfluidic and similar applications is presented. The microvalve is batteryless and can be actuated wirelessly. The security of the device is enhanced by using a coded SAW correlator that is integrated as part of the microvalve. A theoretical analysis of how the actuation mechanism operates is carried out and simulation results of the new microvalve structure are discussed. The ANSYS simulation tool is used to design and simulate the micro-valve structure. Characteristics of the microvalve actuator in terms of displacement for different operating conditions are also discussed.

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Section: Saw Devicesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Surface acoustic wave device based wireless passive microvalve for microfluidic applications

Dissanayake

Al-Sarawi

Abbott

2007

BioMEMS and Nanotechnology III

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“…However such an approach is not suitable for the proposed microvalve design because it is expected to use the output from the SAW device to power the actuator. Considering a generalized application domain, researchers have addressed the possibility of using biomedical implants without batteries for biotelemetry applications and suggest a different principle using the converse piezoelectric effect, to control the microvalve without batteries [4]. The proposed device structure is based on this converse piezoelectric effect combined with a SAW device.…”

Section: Device Operationmentioning

confidence: 99%

“…The required maximum energy for the actuator is taken to be 100nJ [4]. The expected operating frequency of the actuator is taken to be less than 50 Hz because a lower operating frequency provides a better modulation of the fluid flow and results in achieving better fluid flow rates.…”

Section: Figurementioning

confidence: 99%

A radio frequency controlled microvalve for biomedical applications

et al. 2006

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In this paper we propose the use of a RF controlled microvalve for implementation on a PZT substrate for biomedical applications. Such device has a huge range of applications such as parallel mixing of photo-lithographically defined nanolitre volumes, flow control in pneumatically driven microfluidic systems and lab-on-chip applications. The microvalve makes use of direct actuation mechanisms at the microscale level to allow its use in vivo applications. A number of acoustic propagation modes are investigated and their suitability for biomedical applications, in terms of the required displacement, device size and operation frequency. A theoretical model of the Surface Acoustic Wave (SAW) device is presented and its use in micro-valve application was evaluated using ANSYS tools. Furthermore, the wireless aspect of the device is considered through combining the RF antenna with the microvalve simulation by assuming a high carrier frequency with a small peak-to-peak signal. A new microvalve structure which uses a parallel type piezoelectric bimorph actuator was designed and simulated using ANSYS tools. Then, further optimization of the device was carried out to achieve a better coupling between electrical signal and mechanical actuation within the SAW device.

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“…The SAW generated by the IDT propagates along the piezoelectric substrate. The principles of SAW and the SAW generation mechanism in the microvalve are discussed in a previous publication [3]. The high energy density and small size make SAW devices attractive for actuator applications.…”

mentioning

confidence: 99%

Improving the security and actuation of wireless controlled microvalve

et al. 2006

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A wireless microvalve would have a wide range of applications, including biomedical applications such as fertility control and nano-litre drug delivery. Arguably the most important aspect for such a device is a secure method to actuate the valve, such that it is not actuated through the spectrum of electromagnetic radiation already present in the surrounding environment. Additionally, many of the possible applications are sensitive to electromagnetic (EM) radiation so the device should be designed to only require the minimum amount of EM input to actuate the valve. To overcome this problem, we propose the use of a coded interdigital transducer (IDT) to respond only to a coded signal. For the wireless microvalve to be useful in biomedical applications, the IDT's response to a specifically coded RF signal must be much greater than its response to another coded RF signal, even if the two codes are very similar, i.e. improve the signal ratio of the device. In this research we demonstrate a number of code sequences that have a correlation function such that the peak response is unique and can be used to provide a high signal-to-noise ratio (SNR) surface acoustic wave. That results in a unique activation of the device when the interrogating RF signal code sequence matches the stored code sequence in the device. Also we will investigate the trade-off between the needed code length to ensure secure operation and the area constrain of the device within the context of biomedical application. For this purpose, the IDT is modelled as a pulse compression filter, which correlates the input signal with a stored replica.Keywords: microvalve, SAW, IDT, biomedical applications, coded actuators INTORDUCTIONA wireless, battery less microvalve uses no direct electrical power but makes use of the interrogating signal to provide the needed actuation. Such a device can be placed in an inaccessible location thus opening up new host of applications such as flow regulation, on/off switching and sealing of liquids, gases or vacuums [1][2][3]. For this purpose we utilise an IDT configuration with the SAW device. The IDT transforms this incoming RF signal from the antenna to a SAW and vice versa. Wireless interrogation of the device is possible by connecting the IDT to an antenna. The SAW generated by the IDT propagates along the piezoelectric substrate. The principles of SAW and the SAW generation mechanism in the microvalve are discussed in a previous publication [3]. The high energy density and small size make SAW devices attractive for actuator applications. But on the other hand the device requires a high input power level to drive it, hence it is important to have an efficient antenna design and ensure that the device will only trigger to a uniquely coded RF signal. Both of these objectives can be achieved by modelling the IDT as a pulse compression filter thus combining the narrowband, high Q-factor operation of a band pass filter with a coded reception scheme. The coding gain further improves the Q-factor [4]. Since the wirel...

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Trade-Offs for Wireless Transcutaneous RF Communication in Biotelemetric Applications

Cited by 5 publications

References 13 publications

Surface acoustic wave device based wireless passive microvalve for microfluidic applications

Surface acoustic wave device based wireless passive microvalve for microfluidic applications

A radio frequency controlled microvalve for biomedical applications

Improving the security and actuation of wireless controlled microvalve

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