{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T11:16:28Z","timestamp":1780053388303,"version":"3.54.0"},"reference-count":53,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2019,2,20]],"date-time":"2019-02-20T00:00:00Z","timestamp":1550620800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>It has been reported that the frequency bandwidth of capacitive micro-machined ultrasonic transducers (CMUTs) is relatively broader than that of other ceramic-based conventional ultrasonic transducers. In this paper, a feasibility study for orthogonal chirp coded excitation to efficiently make use of the wide bandwidth characteristic of CMUT array is presented. The experimental result shows that the two orthogonal chirps mixed and simultaneously fired in CMUT array can be perfectly separated in decoding process of the received echo signal without sacrificing the frequency bandwidth each chirp. The experimental study also shows that frequency band-divided orthogonal chirps are successfully compressed to two short pulses having the \u22126 dB axial beam-width of 0.26- and 0.31-micro second for high frequency and low frequency chirp, respectively. B-mode image simulations are performed using Field II to estimate the improvement of image quality assuming that the orthogonal chirps designed for the experiments are used for simultaneous transmission multiple-zone focusing (STMF) technique. The simulation results show that the STMF technique used in CMUT array can improve the lateral resolution up to 77.1% and the contrast resolution up to 74.7%, respectively. It is shown that the penetration depth also increases by more than 3 cm.<\/jats:p>","DOI":"10.3390\/s19040883","type":"journal-article","created":{"date-parts":[[2019,2,20]],"date-time":"2019-02-20T11:45:39Z","timestamp":1550663139000},"page":"883","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Orthogonal Chirp Coded Excitation in a Capacitive Micro-machined Ultrasonic Transducer Array for Ultrasound Imaging: A Feasibility Study"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9725-5592","authenticated-orcid":false,"given":"Bae-Hyung","family":"Kim","sequence":"first","affiliation":[{"name":"Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd, Suwon-si, 16678, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seungheun","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Mechanical, Automotive and Robotics Engineering, Dong-eui University, Busan 47340, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kang-Sik","family":"Kim","sequence":"additional","affiliation":[{"name":"Health &amp; Medical Equipment Department, Samsung Electronics Co. Ltd, Suwon-si, 16678, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,2,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1109\/58.143168","article-title":"Coded excitation system for improving the penetration of real-time phased-array imaging systems","volume":"39","year":"1992","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1109\/58.646915","article-title":"Pulse elongation and deconvolution filtering for medical ultrasonic imaging","volume":"45","author":"Haider","year":"1998","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1109\/58.484472","article-title":"A new coded-excitation ultrasound imaging system. i. basic principles","volume":"43","author":"Shen","year":"1996","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_4","first-page":"1469","article-title":"A low voltage portable system using modified golay sequences","volume":"2","author":"Yoo","year":"2001","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1109\/TUFFC.2005.1406545","article-title":"Use of modulated excitation signals in medical ultrasound. Part I: Basic concepts and expected benefits","volume":"52","author":"Misaridis","year":"2005","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_6","first-page":"1677","article-title":"Synthetic transmit aperture imaging using orthogonal golay coded excitation","volume":"2","author":"Chiao","year":"2000","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1109\/TIT.1961.1057620","article-title":"Complementary series","volume":"7","author":"Golay","year":"1961","journal-title":"IRE Trans. Inf. Theory"},{"key":"ref_8","first-page":"1705","article-title":"Orthogonal golay code based ultrasonic imaging without reducing frame rate","volume":"2","author":"Bae","year":"2002","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_9","first-page":"1574","article-title":"Multiple transmit focusing using modified orthogonal golay codes for small scale systems","volume":"2","author":"Kim","year":"2003","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1109\/TUFFC.2005.1406546","article-title":"Use of modulated excitation signals in medical ultrasound. part ii: Design and performance for medical imaging applications","volume":"52","author":"Misaridis","year":"2005","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1109\/TUFFC.2005.1406543","article-title":"Coded excitation for diagnostic ultrasound: A system developer\u2019s perspective","volume":"52","author":"Chiao","year":"2005","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Tong, L., He, Q., Ortega, A., Ramalli, A., Tortoli, P., Luo, J., and D\u2019hooge, J. (2019). Coded Excitation for Crosstalk Suppression in Multi-line Transmit Beamforming: Simulation Study and Experimental Validation. Appl. Sci., 9.","DOI":"10.3390\/app9030486"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1205","DOI":"10.1109\/TMI.2014.2302312","article-title":"Multi-Transmit Beam Forming for Fast Cardiac Imaging\u2014Experimental Validation and In Vivo Application","volume":"33","author":"Tong","year":"2014","journal-title":"IEEE Trans. Med. Imaging"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1977","DOI":"10.1109\/TUFFC.2018.2855042","article-title":"On Combination of Hadamard-Encoded Multipulses and Multiplane Wave Transmission in Contrast-Enhanced Ultrasound Imaging","volume":"65","author":"Gong","year":"2018","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1372","DOI":"10.1109\/TMI.2017.2687400","article-title":"Ultrafast Synthetic Transmit Aperture Imaging Using Hadamard-Encoded Virtual Sources With Overlapping Sub-Apertures","volume":"36","author":"Gong","year":"2017","journal-title":"IEEE Trans. Med. Imaging"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1109\/TUFFC.2011.1810","article-title":"A new synthetic aperture focusing method to suppress the diffraction of ultrasound","volume":"58","author":"Chang","year":"2011","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1109\/58.384453","article-title":"Synthetic aperture imaging for small scale systems","volume":"42","author":"Karaman","year":"1995","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1109\/58.148539","article-title":"Synthetic receive aperture imaging with phase correction for motion and for tissue inhomogeneities. i. basic principles","volume":"39","author":"Nock","year":"1992","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1177\/016173460202400202","article-title":"An efficient motion estimation and compensation method for ultrasound synthetic aperture imaging","volume":"24","author":"Kim","year":"2002","journal-title":"Ultrason. Imaging"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1109\/TUFFC.2003.1182118","article-title":"Dynamic-transmit focusing using time dependent focal zone and center frequency","volume":"50","author":"Zhou","year":"2003","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"204","DOI":"10.4028\/www.scientific.net\/KEM.270-273.204","article-title":"Multiple transmit focusing using modified orthogonal golay codes for ultrasound nondestructive testing","volume":"270","author":"Kim","year":"2004","journal-title":"Key Eng. Mater."},{"key":"ref_22","first-page":"1725","article-title":"A method for simultaneous multi-zone focusing along multiple scan lines using orthogonal codes and its application to multi-dimensional array imaging","volume":"3","author":"Kim","year":"2004","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1109\/TUFFC.2005.1406547","article-title":"Use of modulated excitation signals in medical ultrasound. part iii: High frame rate imaging","volume":"52","author":"Misaridis","year":"2005","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1016\/j.ultras.2007.01.007","article-title":"A post-compression based ultrasound imaging technique for simultaneous transmit multi-zone focusing","volume":"46","author":"Kim","year":"2007","journal-title":"Ultrasonics"},{"key":"ref_25","first-page":"1517","article-title":"Simultaneous multizone focusing method with orthogonal chirp signals","volume":"2","author":"Jeong","year":"2001","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1061","DOI":"10.1109\/TUFFC.2012.2291","article-title":"Orthogonal quadratic chirp signals for simultaneous multi-zone focusing in medical ultrasound imaging","volume":"59","author":"Yoon","year":"2012","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"54004","DOI":"10.1088\/0960-1317\/21\/5\/054004","article-title":"Capacitive micromachined ultrasonic transducers for medical imaging and therapy","volume":"21","author":"Oralkan","year":"2011","journal-title":"J. Micromechanics Microengineering"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1581","DOI":"10.1109\/TUFFC.2003.1251142","article-title":"Volumetric ultrasound imaging using 2-d cmut arrays","volume":"50","author":"Oralkan","year":"2003","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_29","first-page":"407","article-title":"5f-2 packaging and design of reconfigurable arrays for volumetric imaging","volume":"1","author":"Fisher","year":"2007","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1500","DOI":"10.1016\/j.ultrasmedbio.2013.03.002","article-title":"Second harmonic and subharmonic for non-linear wideband contrast imaging using a capacitive micromachined ultrasonic transducer array","volume":"39","author":"Novell","year":"2013","journal-title":"Ultrasound Med. Biol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1127","DOI":"10.1109\/TUFFC.2012.2303","article-title":"A cmut probe for medical ultrasonography: From microfabrication to system integration","volume":"59","author":"Savoia","year":"2012","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_32","first-page":"1428","article-title":"An experimental study on coded excitation in cmut arrays to utilize simultaneous transmission multiple-zone focusing method with frequency divided sub-band chirps","volume":"2","author":"Kim","year":"2013","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_33","first-page":"77","article-title":"Design and test of a fully controllable 64x128 2-D cmut array integrated with reconfigurable frontend asics for volumetric ultrasound imaging","volume":"1","author":"Kim","year":"2012","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"83201A","DOI":"10.1117\/12.911263","article-title":"Reconfigurable 2D cMUT-ASIC arrays for 3D ultrasound image","volume":"8320","author":"Song","year":"2012","journal-title":"Proc. SPIE"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1109\/TBCAS.2016.2571739","article-title":"A single-chip 64-channel ultrasound RX-beamformer including analog front-end and an LUT for non-uniform ADC-sample-clock generation","volume":"11","author":"Kim","year":"2017","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1109\/TBCAS.2014.2375958","article-title":"An analog-digital hybrid RX beamformer chip with non-uniform sampling for ultrasound medical imaging with 2D CMUT array","volume":"8","author":"Um","year":"2014","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Um, J.-Y., Song, E.-W., Kim, Y.J., Cho, S.-E., Chae, M.-K., Song, J., Kim, B.-H., Lee, S., Bang, J., and Kim, Y. (2014, January 9\u201313). 24.8 an analog-digital-hybrid single-chip RX beamformer with non-uniform sampling for 2D-CMUT ultrasound imaging to achieve wide dynamic range of delay and small chip area. Proceedings of the 2014 IEEE International Solid-State Circuits Conference Digest of Technical Papers (ISSCC), San Francisco, CA, USA.","DOI":"10.1109\/ISSCC.2014.6757499"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"3562","DOI":"10.1109\/TED.2013.2278441","article-title":"Three-side buttable integrated ultrasound chip with a 16x16 reconfigurable transceiver and capacitive micromachined ultrasonic transducer array for 3-D ultrasound imaging systems","volume":"60","author":"Jung","year":"2013","journal-title":"IEEE Trans. Electron Devices"},{"key":"ref_39","first-page":"351","article-title":"Field: A program for simulating ultrasound systems","volume":"4","author":"Jensen","year":"1996","journal-title":"Med. Biol. Eng. Comput."},{"key":"ref_40","unstructured":"Peebles, P.Z. (1998). Radar Principles, John Wiley & Sons."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1109\/58.308500","article-title":"Chirp signal matching and signal power optimization in pulse-echo mode ultrasonic nondestructive testing","volume":"41","author":"Pollakowski","year":"1994","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1745","DOI":"10.1016\/j.ultras.2014.03.007","article-title":"Coded waveforms for optimised air-coupled ultrasonic nondestructive evaluation","volume":"54","author":"Hutchins","year":"2014","journal-title":"Ultrasonics"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1530","DOI":"10.1109\/TUFFC.2007.423","article-title":"Elliptical-Tukey chirp signal for high-resolution, air-coupled ultrasonic imaging","volume":"54","author":"Pallav","year":"2007","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"2532","DOI":"10.1109\/TUFFC.2013.2852","article-title":"The effect of amplitude modulation on subharmonic imaging with chirp excitation","volume":"60","author":"Harput","year":"2013","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_45","first-page":"1","article-title":"Pulse Compression in Nondestructive Testing Applications: Reduction of Near Sidelobes Exploiting Reactance Transformation","volume":"99","author":"Burrascano","year":"2018","journal-title":"IEEE Trans. Circuits Syst. I Regul. Pap."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1109\/58.660145","article-title":"Practical spread spectrum pulse compression for ultrasonic tissue imaging","volume":"45","author":"Welch","year":"1998","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_47","unstructured":"Szabo, T.L. (2014). Diagnostic Ultrasound Imaging: Inside Out, Elsevier. [2nd ed.]."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1177\/016173461103300404","article-title":"Ultrasound attenuation measurements using a reference phantom with a sound speed mismatch","volume":"33","author":"Nam","year":"2011","journal-title":"Ultrason. Imaging"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"2733","DOI":"10.1109\/TUFFC.2009.1364","article-title":"Exploitation of capacitive micromachined transducers for nonlinear ultrasound imaging","volume":"56","author":"Novell","year":"2009","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_50","first-page":"2249","article-title":"Tissue harmonic imaging with CMUTs","volume":"2","author":"Legros","year":"2011","journal-title":"Proc. IEEE Ultrason. Symp."},{"key":"ref_51","unstructured":"Macovski, A. (1983). Medical Imaging Systems, Prentice-Hall."},{"key":"ref_52","unstructured":"Goodman, J.W. (1996). Introduction to Fourier Optics, McGraw-Hill. [2nd ed.]."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1698","DOI":"10.1109\/TUFFC.2017.2748165","article-title":"A New Dynamic Complex Baseband Pulse Compression Method for Chirp-Coded Excitation in Medical Ultrasound Imaging","volume":"64","author":"Kang","year":"2017","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/4\/883\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:33:34Z","timestamp":1760186014000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/4\/883"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,2,20]]},"references-count":53,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2019,2]]}},"alternative-id":["s19040883"],"URL":"https:\/\/doi.org\/10.3390\/s19040883","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,2,20]]}}}