Tunable Multiband UWB Pulse Generator Circuit Design Hakim Sabzevari University Supervisor: Dr. Majid Baghaei Nejad By: Seyed Reza Alavi 1

UWB Introduction Ultra-Wideband Pulse Generation Techniques The Proposed Pulse Generator Simulation Results & Discussion Outlines 2

UWB Introduction 3

A series of very short baseband pulses with time duration in nano-seconds Short range Wireless radio communications UWB transmitter signal BW: Bandwidth more than 20% of a center frequency or more 500 MHz Ideal targets for UWB systems: low power low cost high data rates extremely low interference What is UWB? fu-flfu-fl fu+flfu+fl 2 

UWB vs. NB Power Spectral Density (dB) 6% bandwidth Frequency (GHz) Random noise signal 100% bandwidth UWBNB 20% bandwidth 5

High channel capacity  Multi-user network Extremely difficult to detect by unintended users   Highly Secured Superior penetration capability  Can pass through walls and doors Circuit simplicity  Software re-definable High multipath immunity Low cost, low power, nearly all-digital architecture UWB Advantages 6

Communications  Wireless Audio, Data & Video Distribution  RF Tagging & Identification Radar  Collision/Obstacle Avoidance  Intrusion Detection (“see through wall”)  Ground Penetrating Radar Precision Geolocation  Asset Tracking  Personnel localization Potential Application Scenarios 7

Monoband Impulse Radio UWB Single-Band Implementation One pulse occupies the whole BW  Not flexible in the freq. doma  Provides fine time resolution 8

Multiband Impulse Radio UWB The multiband solution provides:  Spectrum flexibility  FD/TD Multiplexing  RF complexity (oscillator) UWB-OFDM option:  Fine frequency control  Increased processing complexity 9

Ultra-Wideband Pulse Generation Techniques 10

Analog Filtering Digital Filtering Digital to Analog Converter based Carrier-based Pulse Generation Techniques 11

 Using a pulse shaping filter to Generate UWB pulses  Not flexible in the frequency and bandwidth selecting  No need synchronization Analog Filtering 12

Digital Filtering  Scaling and adding multiple delayed copies of a baseband impulse  Controllability more readily (pulse waveform & frequency spectrum)  Precise synchronization  High circuit complexity 13

Digital to Analog Converter based  Requiring high sampling rate  Using more advanced technologies such as SiGe BiCMOS  Power-hungry 14

Carrier-based  Based on heterodyning and time- gated oscillators  Flexibility in the frequency and bandwidth selecting  High circuit complexity  Lower synchronization 15

Pulse Generation Techniques Summary Analog Filtering Digital Filtering Digital to Analog Converter based Carrier- based Center frequency controllability PoorNormal High Bandwidth flexibilityPoorNormal High Circuit complexityLowRather High Power consumptionHighNormalHighNormal Occupied area on chipHigh Normal SynchronizationLowPreciseAccurateLow TABLE I: Comparison of different pulse generation techniques 16

The Proposed Pulse Generator 17

The Pulse Generator Architecture 18

The Differential Voltage Control Oscillator 19

The Differential Delay Cell Positive feedback (N3, N4)  Boost the frequency of the oscillator  Reduces the transition time of the output nodes  self-balancing mechanism PMOS transistors (P1, P2) function as loads to control frequency by Vcontrol 20

The Glitch Generator  Producing signals for enabling and heterodyning switches  Controlling the UWB pulse width and output signal spectrum  implemented based on adjustable NOT and NOR gates 21

The Glitch Generator  Determine the duration of the impulse  Varying the inverter charging current by Vdelay  To generate an impulse signal  Tuning the output spectrum by Vimpulse  Providing directly a positive impulse as opposed to a NAND gate 22

The Heterodyning stage Combine the differential signal Pulse shaping DC power=0 Smaller sizes 23

The Buffer stages To achieve sufficient transmitted power Proper output impedance matching Positive feedback (P3, P4)  Boost the operating frequency of buffer stages  To overcome the speed limitation of PMOS transistors 24

The Buffer stages Radiant power can vary as a function of  Pulse rate  Operation distance Variable peak to peak amplitude  By controlling the charge current of last buffer stage by Vamplitude 25

Simulation Results & Discussion 26

Layout Glitch Generators Differential Oscillator Heterodyning stage Buffer stages 27

Oscillator Phase Noise V/sqrt (Hz) (dBc/Hz) Frequency (GHz) Importance in supporting the modulation type Phase noise at 10 MHz offset for different center frequencies  For 3.5 GHz → dBc/Hz  For 4 GHz → dBc/Hz  For 4.5 GHz → dBc/Hz 28

The Generated UWB pulse Pulse width 2.3 ns 528 MHz Bandwidth Center frequency: 4 GHz Maximum peak to peak amplitude: 752 mV 29

Tunable Pulse Amplitude  To use the amplitude modulation  Flexibility in the radiant power  Amplitude variation from 160 mV up to 752 mV Pulse Amplitude (mV) Vamplitude (V) 30

The Generated Pulse Spectrum 528 MHz Bandwidth Center frequencies:  3.5 GHz  4 GHz  4.5 GHz Comply the FCC mask 31

Tunable Pulse Bandwidth Tunable Bandwidth  MHz By controlling the output impulse of glitch generator 32

Available Pulse Rate Maximum pulse rate: 150 MHz UWB pulse waveform in 50 MHz pulse rate UWB pulse waveform in 150 MHz pulse rate 33

Process Variation Simulation Results Validate results in GHz for (tt, ff, snfp, fnsp) corners For ss corner only the first channel is available at 3.5 GHz 34

Temperature Variation Temperature variation from -50 to 50 C˚ Well operating in all three channel  In tempreture upper than 50 C˚, the pulse generator can not comply the third channel 35

Supply Voltage Variation Swept the supply voltage from 1.75 to 2.1 Well operating in all three channel  In voltages from 1.65 to 1.75 V, the pulse generator can not operate in the third channel 36

Performance Summary [41][42][43][44]This work Process (µm) Max. BRF (MHz) Frequency Range (GHz)3– Pulse Bandwidth (MHz) ModulationOOK PPM+ DB-BPSK PPMPPM+ BPSKOOK Output Amplitude (mV) Ep (pJ)N/A Ed (pJ) EfficiencyN/A1.5%7%0.57%4.07% FoM10%11.42%9.3%10.6%9.6% TABLE II: Comparison of performance with other works 37

Research Interests Circuit Level  Different modulations  More controllability  Multi-user techniques  Designing tuning system  Monte Carlo simulation Application Level  Searching for new Applications 38

Relevant Publications S, R, Alawi; H, Khawari; M, Baghaei-Nejad, “A Low Power 900 MHz ISM Band CMOS Ring Oscillator with Wide Tuning Range Control”, 20st Iranian Conference on Electrical Engineering (ICEE 2012), Tehran university, Iran, 2012, (Published ) S, R, Alawi; H, Khawari; M, Baghaei-Nejad, “Tunable Inductorless Multiband Ultra Wideband Pulse Generator”, 21st Iranian Conference on Electrical Engineering (ICEE 2013), Ferdowsi university, Iran, 2013, (Submitted ) S, R, Alawi; H, Khawari; M, Baghaei-Nejad, “A Tunable UWB Pulse Generator with Multiband Channel Selecting ”, 22nd IEEE International Symposium on Industrial Electronics (ISIE 2013), National Taiwan university, Taipei, Taiwan, 2013, (Submitted) 39

Thanks For Your Attention 40