Novel acoustic-surface-wave directional coupler with diverse applications

Marshall, F.G.; Paige, E.G.S.

doi:10.1049/el:19710312

Cited by 77 publications

(4 citation statements)

References 1 publication

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“…The length of each strip is L c , and the spacing between strips is also chosen as L c in this work. In operation, the acoustic waves launched from the input port travel across the strips in the upper half of the waveguide (Track A), alternating potential differences are formed between adjacent strips due to piezoelectricity [61]. Such potential differences between electrodes transfer part of the energy to the lower half of the waveguide (Track B), generating acoustic waves traveling toward both the coupled port and the isolated port.…”

Section: A S0 Msc Overviewmentioning

confidence: 99%

“…Conventionally, RF couplers are based on EM wave interference in coupled transmission lines [57], [58], waveguides [59], or discrete elements [60], of which the sizes are substantial for portable systems. The established acoustic counterparts for EM couplers, namely SAW-based multistrip couplers (MSCs) that employ patterned metallic strips on piezoelectric substrates [61], provide more design flexibilities [12], [13], [62] and drastically smaller sizes. However, three bottlenecks hinder the applications of SAW MSCs.…”

Section: Introductionmentioning

confidence: 99%

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GHz Low-Loss Acoustic RF Couplers in Lithium Niobate Thin Film

Yang

et al. 2020

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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We present the first group of GHz low-loss acoustic radio frequency (RF) couplers using the fundamental symmetric (S0) mode in X-cut lithium niobate thin films. The demonstrated multistrip couplers (MSCs) significantly surpass the insertion loss (IL) and the operating frequency of the previous works in more compact structures, thanks to the large electromechanical coupling and low loss of S0 in lithium niobate. The design space of S0 MSCs is first explored. Devices with different coupling factors are fabricated using different numbers of strips. Based on the S0 testbed with an IL of 4.5 dB at 1 GHz, the hybrid coupler shows an IL of 7.5 dB, while the track changer shows an IL of 5.1 dB, over a 3-dB fractional bandwidth of 8%. Couplers at different frequencies (between 0.75 and 1.55 GHz) are also investigated. Upon further optimizations, the S0 MSC platform can potentially enable low-loss wideband signal processing functions toward an RF acoustic component kit.

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Section: A S0 Msc Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

GHz Low-Loss Acoustic RF Couplers in Lithium Niobate Thin Film

Yang

et al. 2020

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…The BAW affects the performance of the sensor, such as producing some ripples and spurious components in response curve. According to the Reference [ 26 ], the Love wave excited by the IDT i can be transferred to the lower half of the MSC under certain conditions while does not affect the propagation path of the BAW and output from the top half of the MSC. Therefore, we use MSC to separate the Love wave and BAW into two sound paths, which reduces the parasitic response of BAW and improves the performance of the Love wave device.…”

Section: Schematic Diagram Of Love Wave Humidity Sensormentioning

confidence: 99%

Study on Fabrication of ZnO Waveguide Layer for Love Wave Humidity Sensor Based on Magnetron Sputtering

Wen

Niu

et al. 2018

Sensors

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The ZnO waveguide layer for the Love wave humidity sensor was fabricated by radio frequency (RF) magnetron sputtering technique using ZnO as the target material. To investigate the effect of RF magnetron sputtering temperature on the ZnO waveguide layer and Love wave device, a series of Love wave devices with ZnO waveguide layer were fabricated at different sputtering temperatures. The crystal orientation and microstructure of ZnO waveguide was characterized and analyzed, and the response characteristics of the Love wave device were analyzed by network analyzer. Furthermore, a humidity measurement system is designed, and the performance of the Love wave humidity sensor was measured and analyzed. The research results illustrate that the performance of the ZnO waveguide layer is improved when the sputtering temperature changes from 25 °C to 150 °C. However, when the sputtering temperature increases from 150 °C to 200 °C, the performance of the ZnO waveguide layer is degraded. Compared with the other sputtering temperatures, the ZnO waveguide layer fabricated at 150 °C has the best c-axis orientation and the largest average grain size (53.36 nm). The Love wave device has the lowest insertion loss at 150 °C. In addition, when the temperature of the measurement chamber is 25 °C and the relative humidity is in the range of 10% to 80%, the fabricated Love wave humidity sensor with ZnO waveguide layer has good reproducibility and long-term stability. Moreover, the Love wave humidity sensor has high sensitivity of 6.43 kHz/RH and the largest hysteresis error of the sensor is 6%.

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“…According to SAW theory, the frequency response of interdigital transducer (IDT) equals the Fourier transform of the envelope function of IDT, and the frequency response of SAW device with MSC is the product of the transfer functions of two apodized IDTs [12][13][14][15]. In Ref.…”

Section: Principles Of Wavelet Reconstruction Processor Using Saw Devmentioning

confidence: 99%