微創手術無線定位系統之天線設計與系統量測建置

Antenna Design and System Testing for Wireless Navigation Used in Minimally Invasive Surgery

陳鵬宇(Peng-Yu Chen)

指導教授 ： 張嘉展

國立中正大學/工學院/電機工程學系/碩士(2015年)

摘要

本論文以微創手術定位之發送端之天線為研究主軸，與傳統手術相比，微創手術不僅增加了手術上的安全，減小傷口尺寸並使恢復時間加速，但由於可視角受到了極大的限制，故催生出此研究動機。
於本論文中設計了四種天線，包含了環形天線與槽孔天線，其設計受限於手術器械的大小限制。為了能使天線在人體內進行天線量測，需要先了解人體組織的電器特性，包含了介電常數與導電率等，皆需要在天線設計初期便加以考慮。因此，人體模擬組織液在本論文中需對於其量測方法進行討論。而本論文所設計之天線在空氣中或是人體模擬組織液中分別以平面及撓曲的形式進行量測，根據其量測結果，其頻率可操作於2.29 GHz ~ 3.2 GHz，但其量測場型圖並非達到完全的全向性場型。此外，本系統亦有一壓控震盪器可作為發射端之用，其可調電壓可從0 V ~ 10 V，經與器械及天線整合後，並置入人體組織亦進行量測，測得功率大小則為-33.8 dBm。
而第三章則是針對本系統所需之硬體電路及演算法做一簡單的介紹。接收端天線之中心頻率為2.298 GHz，在定位量測角度(-35°~35°)之內其軸比皆小於3 dB。可調控相位範圍可從0° ~ 180°。
最後一章則將詳述定位系統的實驗結果，在一維定位之量測結果中可發現當誤差累積機率達到80%，誤差角度皆小於4°。當置入人體組織以及高密度泡棉手術床墊時，其誤差累積機率在80%時，其誤差角度仍小於5°。而二維定位實驗則加入豬肉組織，結果顯示其最大誤差距離為2.5 cm，而平均誤差距離為0.69 cm。

關鍵字

無線定位 ； 天線 ； 微創手術

並列摘要

In this thesis, a miniaturized antenna design for minimally invasive surgical positioning system is proposed. Comparing to the traditional surgery, the benefits of minimally invasive surgery include increased safety, decreased scarring and faster recovery. However, the limited field of view also brings difficulty, which motivates this work.
Four antennas, including loop antenna and slot antenna, have been designed for surgical instruments with very restricted size limit. In order to carry out the in-body antenna measurement, the electrical characteristic of human tissues, including permittivity and conductivity, need to be considered at the early phase of design. Therefore, the simulated human tissue liquid is also deployed in this work with testing method being discussed. The designed antenna is measured in the air and in the tissue liquid in either plane form or curved form.
According to the result, the operating frequency is from 2.29 GHz to 3.2 GHz, but the radiation pattern isn’t omnidirectional totally. There is an voltage control oscillator(VCO) that be used, the tunable voltage is from 0 V to 10 V, the output frequency is from 2.25 GHz to 2.5 GHz, but the radiation patterns are not as omni-directional as what we expect due to multiple loading effects. A commercial voltage control oscillator (VCO) IC is used as signal source, where that the output frequency is from 2.25 GHz to 2.5 GHz under 0V to 10 V control voltage. The measured output power is -33.8 dBm after being integrated with surgical instrument and antenna is placed in the simulated tissue.
The algorithm and the hardware circuits of the positioning system are briefly introduced in chapter three. The center frequency of received antenna is 2.298 GHz,
the axial ratio is smaller than 3 dB within the spacial range from -35° to 35°. The tunable phase of phase shifter is 0° to 180°.
The demonstrations of the entire positioning system are described in chapter four. For 1-D positioning, the error angle is less than 4 degrees when the accumulation probability is 80%. When placing the simulated tissue and foam mattress, the error angle is still less than five degrees at 80% accumulation probability. In 2-D positioning, we use pork instead of simulated tissue, the maximum error distance is 2.5 cm while the average error distance is 0.69 cm.

並列關鍵字

Wireless Navigation ； Minimally Invasive Surgery ； Antenna Design

參考文獻

[12] M. Brunato, and R. Battiti, “Statistical learning theory for location fingerprinting in wireless LANs,” Comput. Netw., vol. 47, pp, 825-845, 2005.

[13] C. L. Wu, L. C. Fu, and F. L. Lian, “WLAN location determination in ehome via support vector classification,” in Proc. IEEE In. Conf. Netw. Sens. Control, vol. 2, pp. 1026-1031,2004.

[16] B. D. Van Veen and K. M. Buckley, “Beamforming: A versatile approach to spatial filtering,” IEEE ASSP Mag., vol. 5, no. 2, pp. 4-24, Apr. 1988.

[19] P. Bahl and V. N. Padmanabhan, “RADAR: An in-building RF-based user location and tracking system,” in Proc. IEEE INFOCOM 2000, Mar., vol. 2, pp. 775–784.

[20] P. Bahl and V. N. Padmanabhan, “Enhancements to the RADAR user location and tracking system,” Microsoft Corp., Tech. Rep. MSR-TR, Feb. 2000