New miniaturized SAW-sensor array for organic gas detection driven by multiplexed oscillators

Development of a portable electronic nose based on chemical surface acoustic wave array with multiplexed oscillator and readout electronics

“…The SAW oscillators are controlled non-continuously by a multiplexer (MUX, Analog device ADG1406) and a counter (Fairchild semiconductor 74VHC4040) as switching element (Fig. 4b) [19,20]. The readout time of the array is below 1 s, and the SAW devices are designed to operate at 99.8 MHz.…”

A novel electronic nose based on miniaturized SAW sensor arrays coupled with SPME enhanced headspace-analysis and its use for rapid determination of volatile organic compounds in food quality monitoring

“…The frequencies of the devices are read out consecutively using a multiplexing technique [6]. An additional ninth, uncoated SAW device is driven within a single continuously operating oscillator generating a common reference signal for frequency mixing with the single multiplexed sensor signal, respectively.…”

“…coating and sampling techniques, enable highly reproducible detection of volatiles in the ppm and ppb range. Recently, a novel concept to achieve a miniaturized SAW sensor array comprising a dramatic reduction of sampling volume and inner surface area which minimizes response time and unwanted memory effects was presented [6,7]. This system showed already for on-line control of volatile organic compounds (VOC) an excellent longterm stability in combination with good reproducibility and selectivity [8].…”

A fuzzy filter to study the selectivity and sensitivity of a SPME enhanced SAW sensor system characterizing virgin olive oil aroma

“…Eight non-continuously working SAW oscillators were combined into a sensor array, each device being coated with a different coating material to provide chemical selectivity [10]. The frequencies of the devices were gathered consecutively using a multiplexing technique [12], being the read-out period 1 s. An additional uncoated SAW device, driven within a single continuously operating oscillator, was used as a common reference for frequency mixing with the single multiplexed sensor signal. The sensors were permanently purged with nitrogen providing a perfect base line.…”