A tunable analog delay element for high-frequency dynamic beamforming
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Dosyalar
Tarih
2009
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
IEEE
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Implementing beamforming for high frequency arrays is challenging because of the accurate delay requirements at high frequencies. High frequency digital beamforming is not suitable for catheter based applications as a large number of cables is required between the array and the external beamformer. A possible solution is to perform analog beamforming on an integrated circuit adjacent or monolithically integrated to the imaging array. In this study, we introduce an improved voltage in voltage out low pass filter as an analog delay cell for high frequency dynamic beamformers. This circuit can generate three times more delay with a given bandwidth when compared to conventional low pass filters. Delay of the circuit is tunable and the gain of the cell is inherently very close to unity. The proposed delay cell operates single ended and therefore is more suitable for CMUT operation which generates single ended output. We designed a test beamformer for a 30MHz, equal area, annular array with 100% bandwidth using the proposed delay cell and the unit-delay focusing architecture. Required delays are implemented using a delay line made up of improved delay elements with tunable delays. To demonstrate functionality we designed and fabricated a custom front-end IC in a 0.5µm standard CMOS process. The IC chip consists of 8 transimpedance amplifiers, voltage-to-current converters, the analog dynamic beamformer, and two buffers. We present results of preliminary imaging experiments that demonstrate the focusing capability.
Açıklama
Anahtar Kelimeler
Analog beamforming, Analog integrated circuits, Annular array, Array signal processing, Bandwidth, Beam formers, Beamforming, Biomedical ultrasonics, Capacitive micromachined, Catheter, Catheters, Circuit delay, CMOS integrated circuits, CMUT operation, CMUTs, Custom front-end IC, Delay, Delay filters, Delay line, Delay lines, Delay cell, Delay circuits, Delay elements, Differential amplifiers, Digital beam forming, Focusing, Frequency, Frequency 30 MHz, High frequency, High frequency arrays, High frequency dynamics, High-frequency dynamic beamforming, High-frequency ultrasound, IC chips, Imaging arrays, Imaging experiments, Low pass filter, Low pass filters, Low-pass filters, Monolithically integrated, Possible solutions, Single-ended, Standard CMOS process, Transimpedance amplifiers, Tunable analog delay element, Tunable circuits and devices, Tunable delay, Ultrasonic imaging, Ultrasonic transducers, Ultrasonics, Voltage, Voltage-to-current converters
Kaynak
Proceedings - IEEE Ultrasonics Symposium
WoS Q Değeri
Scopus Q Değeri
N/A
Cilt
Sayı
Künye
Gürün, G., Şisman, A., Zahorian, J., Satir, S., Karaman, M., Hasler, P. & Değertekin, F. L. (2009). A tunable analog delay element for high-frequency dynamic beamforming. Paper presented at the 345-348. doi:10.1109/ULTSYM.2009.5441823
