VIRTUS, IC Design Centre of Excellence 280GHz CMOS On-chip Composite Right/Left Handed Transmission Line based Leaky Wave Antenna with Broadside Radiation YangShang, Hao Yu*, Peng Li, Yuan Liang, and Chang Yang School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, E-mail: [email protected] NTU CMOS Emerging Technology Group Outline • Background and Motivation • CRLH T-line Based Leaky Wave Antenna Design • Antenna Layout and Simulation • Measurements • Conclusion NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 2 Background and Motivation (0.1~10THz) General Specifications for medical imaging 1. Resolution: Penetration depth: 3~5 mm (Sensitive to thin tissue); Spatial resolution: ~ 200 μm; Depth resolution in the skin: ~ 40 μm (3D Imaging) 2. Species-specific spectral absorption of THz energy: Sensitive to Hbond vibration 3. Non-ionizing : not harmful to body [“Terahertz imaging comes into view”, Physics world, 2001] [“A promising diagnostic method: Terahertz pulsed imaging and spectroscopy”, World J Radiol 2011 March 28; 3(3): 55-65] NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 3 Design Challenges of THz Imaging System • Propagation loss is high! • High gain on-chip antenna! • Compact phasearrayed metamaterial antenna at THz [T. Schneider et al., “Link Budget Analysis for Terahertz Fixed Wireless Links”, IEEE Transactions On Terahertz Science And Technology, Vol. 2, No. 2, Mar.2012.] NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 4 What is Metamaterial? NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 5 Metamaterial : CRLH T-line Left-handed 2.0 Region Bandgap Region β 1.5 1.0 Dispersion Diagram: α 0.5 0.0 -0.5 Righthanded Region -1.0 -1.5 -2.0 20 40 60 80 100 120 140 160 180 200 Low Stop Band Frequency (GHz)High Stop Band NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 6 Leaky Wave Antenna Design by CRLH T-line Composite Right/Left Handed Transmission Line (CRLH T-line) Equivalent Circuit for Unit Cell NTU CMOS Emerging Technology Group Structure of on-chip CRLH unit-cell 4th VIRTUS Annual Postgraduate Research Workshop 7 CRLH T-line Based Leaky Wave Antenna(LWA) Design LWA: Traveling wave structure with periodic radiation aperture Y θMB Z k0 β>0 ky (a) k0= ky β= 0 β<0 (c) Equal Magnitude Line CRLH T-line Main beam radiation angle: NTU CMOS Emerging Technology Group ky (b) Equal Phase Line θ MB =arcsin ( β k 0 ) k0 • CRLH T-line: β Conventional T-line >, < and = 0 Only >0 4th VIRTUS Annual Postgraduate Research Workshop 8 Antenna Layout • GF CMOS65nm Antenna Layer Configuration 13 cells P1 P2 Wf Wp Air Si Layer Substrate gp Lp Wm 13-cell CRLH Tline LWA Test Structure Layer Configuration Air dm Unit Cell 100 μm Wm ` Lf Wf=3μm, Lf=43μm gp=2μm, Wp=4μm Lp=32μm, Wm=3.5μm dm = 12μm Via Bar(M1 ~ LB) GND NTU CMOS Emerging Technology Group Substrate 13-cell CRLH T-line 4th VIRTUS Annual Postgraduate Research Workshop 9 Simulation Results 100 90 80 70 60 50 40 30 20 10 0 no High-Resitivity Si layer High-Resitivity Si layer Enhancement 25 20 Enhancement Radiation Efficiency (%) After stacking the dielectric layer of with high resistivity of Si enhanced to 40.5~65.2%. The maximum antenna gain of 4.1dBi is achieved at 280GHz. 15 10 230 240 250 260 270 280 290 Frequency (GHz) NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 10 Measurement Results 10 -10 200 5 150 0 100 S21 (dB) S11 (dB) -10 -15 -15 -20 S21 Measurement S21 HFSS S21 Circuit S11 Measurement S11 HFSS S11 Circuit -20 -25 -25 -30 220 230 240 250 260 270 280 290 300 310 320 Phase(S11) Measurement Phase(S11) HFSS Phase(S11) Circuit |β| Measurement |β| HFSS |β| Circuit K0 50 β<k0 0 2.8Ω CL 9k 8k 7k 6k 5k 4k -50 3k -100 2k -150 1k -200 220 0 240 260 280 300 320 Frequency (GHz) Frequency (GHz) RS 10k LL CR LR GL 14.7fF 28.3pH 13.8fF 15.6pH 1.3mS NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 11 |β| (Rad/m) -5 Phase(S11) (Deg) -5 Conclusion • A composite right/left handed transmission line is demonstrated with measurement results from 220 to 325GHz in 65nm CMOS process for the leaky wave antenna (LWA) design with broadside radiation. – Stacking of dielectric layer with high resistivity of Si is utilized to improve the LWA efficiency – The propose antenna design has radiation efficiency of 65%, and the antenna gain of 4.1dBi at 280GHz – The proposed compact LWA structure can be potentially deployed for the design of on-chip THz phase-arrayed antenna NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 12 Acknowledgement • Simulation: EMX from Integrand Software • Measurement: VIRTUS IC Design Centre of Excellence at Nanyang Technological University • Funding and Support: Singapore MOE Tier-1 Funding and Global Foundries and MediaTek sponsorship for CMOS 65nm tapeouts NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 13 Thank You! Q&A http://www.ntucmosetgp.net Email: [email protected] Skype: hao.yu.ntu NTU CMOS Emerging Technology Group 4th VIRTUS Annual Postgraduate Research Workshop 14
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