Ultra-wideband Pulse Generator Research Articles

GENERATION OF RECTANGULAR NANOSECOND ELECTROMAGNETIC PULSES WITH A PICOSECONDS RISE FRONT

A method for generation of ultra-wideband electromagnetic pulses with a nanosecond duration and a picosecond rise time has been studied. The emitter is a horn antenna with a photoconductive switch irradiated by laser pulses. It has been shown that the duration of ultra-wideband electromagnetic pulses is determined by the length of the antenna and the semiconductor material, and the rising front is determined by the front of the laser pulses used to initiate the photoconductive switch. The work shows typical pulse durations of ~1 ns with a rising edge of up to ~34 ps.

A photo-controlled, all-solid, and frequency-tunable ultra-wideband pulse generator.

With the continuous exploration of the bioelectric effect, nanosecond and picosecond pulsed electric fields used in cancer therapy and drug introduction have attracted great attention. In this paper, an ultrashort pulsed electric field generator is proposed, which connects two photoconductive semiconductor switches in parallel to generate unipolar and bipolar pulses. We described the experimental scheme of the generator and the simulation of the radio frequency combiner. A 532nm laser with pulse widths of 1ns and 500ps is used to trigger the photoconductive semiconductor switches. The experimental results show that the scheme can achieve adjustments of 357 and 720MHz for the center frequency and the 3 dB bandwidth, respectively. The results confirm that this proposed scheme can be used for unipolar/bipolar frequency-adjustable ultra-wideband pulse generation.

A compact ultra-wideband sub-nanosecond pulse generator with step recovery diodes

This article presents a compact ultra-wideband (UWB) sub-nanosecond monocycle pulse generator. The proposed circuit has a simple structure and low cost, and its core components are step recovery diodes (SRDs). It is composed of a power supply circuit, pulse drive circuit, short pulse-forming circuit, and pulse-shaping circuit. A transistor-based drive circuit is used to generate a drive pulse with sharp fall time. Then, a sub-nanosecond pulse width is realized through the combination of two SRDs in series and parallel. Finally, a monocycle pulse is directly formed by the inductance-based differentiator. This design achieves a full pulse width of 406 ps with a 260 mV peak-to-peak amplitude and a −10 dB bandwidth of 510 MHz to 6.1 GHz at a pulse repetition frequency of 10 MHz square waveform. The symmetry and ringing level are 96.9% and −25.3 dB, respectively, providing good symmetry and low ringing with a circuit size of 55 × 15 mm. In actual experiments, two identical UWB antennas with appropriate bandwidth are used to radiate a monopulse to breast phantoms. The results and uncertainty analyses of the test system show that there are distinguishable differences under diverse tumor phantoms and locations, proving that the proposed pulse generator is attractive for the application of UWB breast cancer detection.

Design of an ultra‐wideband picosecond pulse generator based on step recovery diodes with an improved SPICE model

SummaryThis article proposed an ultra‐wideband ultra‐short picosecond pulse generator based on step recovery diodes (SRDs). The equivalent circuit model of SRD is analyzed, and an improved nonlinear simulation program with integrated circuit emphasis (SPICE) model is presented for appropriate circuit simulation in Advanced Design System (ADS) software. An external direct current (DC) voltage source is added to bias the SRD. In this article, a conventional shunt SRD topology configuration is developed to generate the Gaussian pulse. According to the measured data, the Gaussian pulse duration for the shunt SRD pulse generator is 210 ps, with the full width at half‐maximum (FWHM) of 110 ps, and the ringing level is −7.8 dB. Moreover, to further improve the tail ringing level, an SRD's mixed topology configuration is introduced and fabricated. The experimental results indicate that the two SRD mixed pulse generator has a pulse duration of 220 ps with FWHM of 120 ps, validating the reasonability of the improved SRD nonlinear SPICE model in ADS. Additionally, there is a considerable improvement in the ringing level of −11.4 dB.

Detection and Localization of Breast Cancer Using UWB Microwave Technology and CNN-LSTM Framework

Ultrawideband (UWB) microwave detection technology, which is low cost and harmless, has been intensively studied and developed for breast cancer detection. In this study, a composite end-to-end framework that consists of convolutional neural network (CNN) and long-short-term memory (LSTM) is proposed, which can realize the tasks of detecting and quadrant locating the breast tumor simultaneously without any complicated microwave imaging processing. In order to verify the proposed network, three datasets are constructed. First, the microwave signals are solved by the auxiliary differential equation-finite-difference time-domain (ADE-FDTD) solver and the magnetic resonance imaging (MRI)-derived breast models with varied breast densities. Then, Simulation datasets 1 and 2 with varied dielectric properties are constructed. Furthermore, an experimental dataset is constructed through an experimental system consisting of the UWB pulse generation module, UWB antennas, the realistic breast phantom, and sampling oscilloscope. With the proposed network, the overall prediction accuracies of the three datasets reach 99.56%, 98.94%, and 89.50%. These promising results demonstrate the effectiveness and accuracy of the proposed deep learning framework for microwave breast cancer detection.

Experimental Generation of Reconfigurable Ultra-Wideband Signal Based on the Pulse Difference by Using Optical Polarization Synthesis

A reconfigurable optical ultra-wideband (UWB) pulse generation scheme based on the pulse difference by using polarization synthesis is proposed and demonstrated experimentally. The Gaussian pulses with an appropriate time delay are modulated via the two sub-MZMs of the DPol-MZM, and the optically carried signals are combined via orthogonal polarization multiplexing, avoiding the optical interference. By setting the DC bias voltages of the sub-MZMs and the time delay, a pair of polarity-reversed Gaussian monocycle, doublet, triplet and quadruplet signals are generated with the central frequency of 3.37, 4.79, 4.5, 5.05 GHz and the fractional bandwidths of 166%, 129%, 124%, 89% accordingly. The signals of pulse shape modulation, binary phase shift keying modulation and on-off keying modulation are generated with the experimental system.

Design and Performance Analysis of a Picosecond Pulse Generator

A picosecond pulse generator is designed to generate a stable differentiated Gaussian (monocycle) waveform. The design approach to increasing the center frequency, bandwidth and peak-to-peak voltage, as compared to previously reported ultra-wideband (UWB) generators, is described. The 280 ps wide pulse achieves a 1:10 fractional bandwidth (FBW) ratio extending from 500 MHz to beyond 5 GHz at the -10 dB level. A measurement procedure is proposed for evaluating the jitter and noise performance of UWB pulse generators, and it is applied to the fabricated prototype. The procedure exploits jitter and noise definitions from high-speed digital electronics, which are adapted here for the jitter and noise evaluation of UWB pulse generators at microwave frequencies. The problems in obtaining the absolute and relative jitter of a UWB generator are discussed along with proposed solutions. The impact of the input trigger on the pulse stability is demonstrated through the dramatic improvement achieved by the integration of a jitter cleaner in the generator’s circuit.

Design and Device Mismatch Analysis of CSS–UWB Pulse Generator

This paper presents the design of a Chirp Spread Spectrum (CSS), ultra-wideband (UWB), pulse generator (PG) and device mismatch impact on its performance. The proposed CSS-PG is built using a differential ring oscillator (RO) controlled by a ramp generator, allowing varying linearly the pulse frequency with time over the CSS pulse duration. Device mismatches and random variations during integrated circuit manufacturing are the most critical imperfections in high precision differential UWB voltage controlled RO circuit. These mismatches lead to behavioral variations of the PG. The proposed CSS-UWB-PG is designed and analyzed using CMOS 0.18[Formula: see text][Formula: see text]m technology. The CSS-PG presents an output swing of 266[Formula: see text]mV Vpp for 20[Formula: see text]nsec and consumes 1.72[Formula: see text]mW for a PRF of 10[Formula: see text]MHz. The simulated PSD covers the UWB low band from 3[Formula: see text]GHz to 5[Formula: see text]GHz and complies with the FCC regulations. For [Formula: see text] mismatch, the simulation results show a maximum relative accuracy on oscillation frequency and phase noise of 3.43% and 6.9%, respectively. Monte Carlo and process simulation are performed to study the impact of the random parameter variation on this CSS-PG. Theses simulations show the robustness of the proposed design as the PG PSD is still inside the FCC-UWB mask and its bandwidth is greater than 500[Formula: see text]MHz.

A 27 dB Sidelobe Suppression, 1.12 GHz BW−10dB UWB Pulse Generator With Process Compensation

This brief presents an on-off keying (OOK) driven impulse radio ultra-wideband (IR-UWB) pulse generator (PG) for 3-5 GHz applications, featuring high sidelobe suppression (SLS), large bandwidth ( BW <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10dB</sub> ), and robustness against process variations. To eliminate the need for a dedicated off-chip pulse-shaping filter, a transistor-sizing-based pulse shaping scheme is adopted to generate a broadband pulse with a triangular envelope, ensuring enhanced SLS with extended signal bandwidth. The proposed process compensating circuit mitigates the effects of process variations on the propagation delay of the logic gates to provide stable pulse timing characteristics. Implemented in 65-nm CMOS process, the prototype PG provides a UWB pulse with an amplitude of 634 mV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pp</sub> , BW <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10dB</sub> of 1.12 GHz, and 27 dB SLS, while occupying a total chip area of 964 μm × 669 μm. The proposed PG provides enhanced pulse characteristics with modest energy consumption among the reported works. Based on the proposed figure-of-merit considering the SLS and quality of pulse, the PG in this work shows a competitive FOM of 3.36×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup> .

A Compact High-Power Ultra-Wideband Bipolar Pulse Generator

A compact high-power ultra-wideband bipolar pulse generator based on a modified Marx circuit is designed, which is mainly composed of a primary power supply, Marx generator, sharpening and cutoff subnanosecond spark gap switches, and coaxial transmission lines. The Marx generator with modified circuit structure has thirty-two stages and is composed of eight disk-like modules. Each module consists of four capacitors, two spark gap switches, four charging inductors, and a mechanical support. To simplify the design of the charging structure and reduce the number of switches, four groups of inductors are used to charge the capacitors of the Marx generator, two of which are used for positive voltage charging and the other two for negative voltage charging. When the capacitor of each stage is charged to 35 kV, the maximum output peak voltage can reach 1 MV when the Marx generator is open circuit. The high-voltage pulse generated by the Marx generator charges the transmission line and forms a bipolar pulse through sharpening and cutoff switches. All transmission lines used for bipolar pulse generation have an impedance of 10 Ω. When the 950 kV pulse voltage generated by the Marx generator is fed into the transmission line, the bipolar pulse peak voltage can reach 390 kV, the center frequency of the pulse is about 400 MHz, and the output peak power is about 15.2 GW.

A Tunable CMOS IR-UWB Pulse Generator Based on Feedback Controlled Oscillator Switching

This brief presents a tunable Impulse-Radio Ultra-Wideband (IR-UWB) pulse generator based on feedback oscillator switching. The circuit provides a wide range of pulse amplitude and width tuning, thus enabling the required pulse shaping for a desired pulse repetition rate and/or a wireless transmission range. Feedback controlled switching prevents the potential omission of the UWB pulse generation and provides low UWB pulse energy variations at low bias currents and a wide temperature range, ensuring system robustness with respect to temperature variations. The pulse amplitude is tunable within 0.27 Vpp to 2.05 Vpp, while the pulse width tuning range is 1-6.5 ns. The total energy consumption of the IR-UWB pulse generator at the 50 Mpps pulse repetition rate is equal to 25.4 pJ/pulse for the pulse amplitude equal to 0.27 Vpp, while for the pulse amplitude equal to 2.05 Vpp, it is increased up to 99.8 pJ/pulse. The circuit occupies a core area of 0.56 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in a 0.18 μm CMOS technology.

Optical generation of UWB pulses utilizing Fano resonance modulation.

In this paper, we reported an integrated method to generate ultra-wideband (UWB) pulses of different orders based on a reconfigurable silicon micro-ring resonator-coupled Mach-Zehnder interferometer. Under proper operating conditions, the device can produce Fano resonances with a peak-to-valley extinction ratio of above 20 dB. UWB monocycle and doublet signals with picosecond pulse widths are produced when the microring resonator is modulated by square and Gaussian electrical pulses, respectively. With our Fano resonance modulator on silicon photonics, it is promising to foresee versatile on-chip microwave signal generation.

A High-Voltage UWB Pulse Generator Using Passive Amplification in 65-nm CMOS

This paper proposes an ultra-wideband (UWB) pulse generator featuring high output amplitude for applications with long transmission and detection range. The output signal of a switch-mode power amplifier stage is passively amplified by a wideband matching network to produce output voltage amplitudes beyond the supply voltage level. Incorporating the parallel LC load of the power amplifier into the matching network and considering the constraints of the wideband matching when the power amplifier is ON and OFF, only a 2-section matching network is added for wideband matching. Employing a trapezoidal waveform as the input signal of the power amplifier, the design flexibility of the matching network to generate a regulation-compliant UWB pulse is further extended. Implemented in a 1-V 65-nm CMOS process, the proposed UWB pulse generator produces a UWB pulse with a de-embedded peak-to-peak amplitude (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pp</sub> ) of 2.49 V, a bandwidth of 6.8 GHz and pulse duration of 0.5 ns achieving 249% peak-to-peak to supply voltage ratio.

Circuit analysis and optimisation of the high‐voltage high‐efficiency IR‐UWB pulse generator for ranging and radar application

An in-depth circuital analysis of an energy-efficient high peak power impulse radio ultra-wideband (IR-UWB) pulse generator monolithic microwave integrated circuit (MMIC) design is presented. The proposed IR-UWB pulse generation process is explained in detail. A trade-off between the peak output power level and the frequency of operation is discussed. The proposed circuit is optimised for the highest possible peak output power in the 3–5 GHz UWB band for ranging and radar application. The presented IR-UWB pulse former makes use of the cascode heterojunction bipolar transistor (HBT) configuration for signal scaling operation instead of the common emitter configuration. The proposed cascode pair configuration results in higher output voltage swing as well as reduced power consumption. The effect of coupling capacitors on amplification factor of the pulse former stages as well as impedance profile of the distributed transmission line is discussed in great detail. The temperature-dependent parasitic component in the proposed circuit is studied. Its effect on the transient behaviour of the proposed IR-UWB pulse generator is analysed, which is important for IR-UWB beamforming applications. The required mathematical model for the parasitic effect is derived and explained.

An Efficient Ultrawideband Pulse Transmitter With Automatic On–Off Functionality for Primary Radar Systems

This letter proposes an ultrawideband (UWB) transmitter for a UWB primary impulse radar that is designed for real-time pedestrian localization. The proposed transmitter applies a novel combination of a UWB pulse generator followed by a UWB amplifier to boost output pulse amplitude, which is able to be turned off automatically after one pulse transmission in order to reduce power consumption. The transmitter has been fabricated using 45-nm SOI CMOS technology and has been measured on a printed circuit board (PCB). The produced pulses possess a high measured peak-to-peak amplitude of 425 mV and a width of around 600 ps. The power spectral density (PSD) of the pulse achieves a maximum of −41 dBm/MHz at 6 GHz with a −10-dB bandwidth of 4.5 GHz from 3.3 to 7.8 GHz that assures that the proposed transmitter complies with the regulation of the U.S. Federal Communications Commission (FCC) for UWB outdoor applications. The pulse generator consumes around 10 pJ/pulse from a 1-V supply, which is very low among the similar designs, and remains almost constant with an increasing pulse repetition time (PRT).

A 0.5 nJ/b 60 GHz ultra wideband transmitter for short range wireless sensor network applications

AbstractA novel monolithic microwave integrated circuit (MMIC) design of ultra wide band (UWB) transmitter at 60 GHz with simple architecture and high‐range resolution ability is presented in this paper. Implemented with 0.1 μm 100 GHz GaAs positive channel high electron mobility transistor (PHEMT) technology offered by OMMIC, the transmitter comprises a millimeter wave oscillator, a buffer amplifier (BA), a medium power amplifier (MPA) and two UWB Pulse Generators (UWBPG). For the sake of the goal on reducing the entire transmitter consumption, the oscillator is controlled by one UWBPG and another UWBPG drives the BA and MPA simultaneously. The transmitter has infinite isolation level to minimize the interference with neighboring devices. For a pulse repetitive time of 5 ns, pulse width of 500 ps and supply voltage of 3 V, the transmitter consumes only 101 mW and has a peak transmit power of 9.2 dBm corresponding to 0.5 nJ per pulse energy consumption, which is suitable for future short range wireless sensor network (WSN) applications.

A 2.12-V $V_{pp}~11.67$ -pJ/pulse Fully Integrated UWB Pulse Generator in 65-nm CMOS Technology

This paper presents a high-voltage ultra-wideband (UWB) pulse generator. Shifting the UWB signal synthesis to digital domain using two consecutive trapezoidal waves, the design requires only a simple low-loss passive filter to conform to UWB spectrum regulations. A power amplifier stage is added to boost the output voltage above the supply voltage limit. To verify the design concept, the generator is designed in TSMC CMOS 65 nm technology with 1 V supply voltage occupying a die size of 0.34 mm2. The UWB generator achieves an efficiency of 21% while the total energy consumption is 11.67 pJ/pulse. On-chip measurement is in good agreement with the simulation and shows output peak-to-peak amplitude of 2.12 V after adding the cable and probe losses to the measured 1.62 V peak-to-peak voltage. The proposed UWB signal generator achieves the highest peak-to-peak to supply voltage ratio among the UWB signal generators reported to the date.

DDS-Based Flexible UWB Pulse Generator Using Anti-Nyquist Sampling Theorem

A real all-digital and all-coherent arbitrary ultra wideband pulse generator is presented. The generator is a multi-core & single-channel (MCSC) direct-digital-synthesizer (DDS) which consists of 16 sub-cores and a high speed digital analog converter AD9739. The ultra-wideband pulses are generated according to the proposed anti-Nyquist sampling theorem. Their frequencies are aliasing in the first and second Nyquist zones. By purposely aliasing the spectrum, the output bandwidth can be increased greatly. All the parameters including pulse width, bandwidth, amplitude, pulse type, pulse repeat frequency and modulation are user-controlled on-the-fly. In order to test the performance, monopole pulse, monocycle pulse and two 4th order Gaussian pulses are generated. The monopole pulse whose pulse rate can achieve 2.5 GHz has a 10% pulse width of 450 ps, a 200 mV peak amplitude and a -10 dB bandwidth of 2.15 GHz.

FCC-compliant millimeter-wave ultra-wideband pulse generator based on optoelectronic oscillation.

We report a photonic scheme to generate a millimeter-wave ultra-wideband (MMW-UWB) pulse based on optoelectronic oscillation (OEO). Normally, a millimeter-wave signal source is essential for the generation of a MMW-UWB pulse. The key novelty of our work is that no millimeter-wave signal source is required. The MMW-UWB pulses are directly generated by truncating an OEO signal into pulses. The principle behind the proposed scheme is analyzed in detail. A proof-of-concept experiment shows that the generated MMW-UWB pulses fit the Federal Communications Commission (FCC) spectral mask very well.

An Energy Efficient Multi-User Asynchronous Wireless Transmitter for Biomedical Signal Acquisition.

The paper presents a novel transmitter architecture for short-range asynchronous wireless communication, applicable to simultaneous multi-user wireless acquisition of biological signals. The analog signal, provided from an analog biosensor, is transformed to time information using an Integral Pulse Frequency Modulator (IPFM) as a Time-Encoding Machine. The IPFM generates a time-encoded unipolar pulse train, maintaining the linear dependence of the output pulse distance on analog input voltage. The system enables continuous acquisition of the signals from multiple sensors in which each transmitter has unique feedback loop delay used for multi-user coding. IPFM pulses trigger the Impulse Radio Ultra-Wideband pulse generator directly, providing two ultra-wideband (UWB) pulses per each IPFM pulse. Due to the lack of internal clock signal and microprocessor-free multi-user coding, the circuitry satisfies the requirements of multi-user coding energy efficiency and size reduction, which are crucial demands in biomedical applications. The proposed Time-Encoded UWB (TE-UWB) transmitter is implemented in 0.18 [Formula: see text] CMOS technology. Measurement results of the IPFM transfer function for input voltage ranging from 0.15 to 1.5 V are presented, providing the dependence of the IPFM pulse time distance on analog input voltage and power consumption dependence on the input voltage level. For continuous monitoring operation, total power consumption of the transmitter circuitry for the maximum input voltage is 10.8 [Formula: see text], while for the lowest input voltage it increases to 40.48[Formula: see text]. The circuit occupies 0.14 [Formula: see text].