A Fully-Integrated Reconfigurable Dual-Band Transceiver for Short Range Wireless Communications in 180 nm CMOS

© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.A fully-integrated reconfigurable dual-band (760-960 MHz and 2.4-2.5 GHz) transceiver (TRX) for short range wireless communications is presented. The TRX consists of two individually-optimized RF front-ends for each band and one shared power-scalable analog baseband. The sub-GHz receiver has achieved the maximum 75 dBc 3rd-order harmonic rejection ratio (HRR3) by inserting a Q-enhanced notch filtering RF amplifier (RFA). In 2.4 GHz band, a single-ended-to-differential RFA with gain/phase imbalance compensation is proposed in the receiver. A ΣΔ fractional-N PLL frequency synthesizer with two switchable Class-C VCOs is employed to provide the LOs. Moreover, the integrated multi-mode PAs achieve the output P1dB (OP1dB) of 16.3 dBm and 14.1 dBm with both 25% PAE for sub-GHz and 2.4 GHz bands, respectively. A power-control loop is proposed to detect the input signal PAPR in real-time and flexibly reconfigure the PA's operation modes to enhance the back-off efficiency. With this proposed technique, the PAE of the sub-GHz PA is improved by x3.24 and x1.41 at 9 dB and 3 dB back-off powers, respectively, and the PAE of the 2.4 GHz PA is improved by x2.17 at 6 dB back-off power. The presented transceiver has achieved comparable or even better performance in terms of noise figure, HRR, OP1dB and power efficiency compared with the state-of-the-art.Peer reviewe

ISM S-Band CubeSat Radio designed for the PolySat System Board

Cal Poly’s PolySat CubeSat satellites have begun to conduct more complex and scientifically significant experiments. The large data products generated by these missions demonstrate the necessity for higher data rate communication than currently provided by the PolySat UHF radio. This thesis leverages the proliferation of consumer wireless monolithic transceivers to develop a 250kbps to 2000kbps, 2W CubeSat radio operating within the 2.45GHz Industrial, Scientific, and Medical (ISM) radio band. Estimating a link budget for a realistic CubeSat leads to the conclusion that this system will require a large deployable CubeSat antenna, large earth station satellite dish, and a fine-pointing attitude control system. Noise floor measurements of a CubeSat ground station demonstrate that terrestrial ISM interference can be minimized to below the thermal noise floor by carefully choosing the operating frequency. The radio is specifically designed as a daughter board for the PolySat System Board with a direct interface to the embedded Linux microprocessor. A state-of-the-art ZigBee transceiver evaluation board is measured to confirm its suitability for a CubeSat radio. A schematic is developed, which integrates the transceiver, power amplifier, low noise amplifier, amplifier protection circuitry, switching regulators, and RF power measurement into a single printed circuit board assembly (PCBA). The circuitry is then squeezed into a high-density, 1.4” x 3.3” layout. The PCBA is then manufactured, troubleshot, tuned, and characterized

Characterizing Cyclostationary Features of Digital Modulated Signals with Empirical Measurements Using Spectral Correlation Function

Signal detection is widely used in many applications. Some examples include Cognitive Radio (CR) and military intelligence. CRs use signal detection to sense spectral occupancy. Without guaranteed signal detection, a CR cannot reliably perform its role. Similarly, signal detection is the first step for garnering an opponent\u27s information. Wireless signal detection can be performed using many different techniques. Some of the most popular include matched filters, energy detectors (which use measurements such as the Power Spectral Density (PSD) of the signal), and Cyclostationary Feature Detectors (CFD). Among these techniques, CFD can be viewed as a compromise technique, in that it theoretically has better low Signal-to-Noise Ratio (SNR) detection performance than energy detectors and less strict requirements than matched filters. CFD uses the cyclostationarity of a signal to detect its presence. Signals that have cyclostationarity exhibit correlations between widely separated spectral components. Functions that describe this cyclostationarity include the Spectral Correlation Function (SCF). One advantage of cyclostationary approaches such as these is that Additive White Gaussian Noise (AWGN) is cancelled in these functions. This characteristic makes SCF outperform PSD under low SNR environments. However, whereas PSD has been well investigated through empirical experiments throughout many researches, SCF features under real world noise have not been investigated with empirical experiments. In this effort, firstly, the SCF features of modulated signals under real world channel noise are identified and characterized using the concept of path loss. Secondly, outperformance of SCF under low SNR environment with real world signals is verified with real world signals and noise

Ultra Small Antenna and Low Power Receiver for Smart Dust Wireless Sensor Networks

Wireless Sensor Networks have the potential for profound impact on our daily lives. Smart Dust Wireless Sensor Networks (SDWSNs) are emerging members of the Wireless Sensor Network family with strict requirements on communication node sizes (1 cubic centimeter) and power consumption (< 2mW during short on-states). In addition, the large number of communication nodes needed in SDWSN require highly integrated solutions. This dissertation develops new design techniques for low-volume antennas and low-power receivers for SDWSN applications. In addition, it devises an antenna and low noise amplifier co-design methodology to increase the level of design integration, reduce receiver noise, and reduce the development cycle. This dissertation first establishes stringent principles for designing SDWSN electrically small antennas (ESAs). Based on these principles, a new ESA, the F-Inverted Compact Antenna (FICA), is designed at 916MHz. This FICA has a significant advantage in that it uses a small-size ground plane. The volume of this FICA (including the ground plane) is only 7% of other state-of-the-art ESAs, while its efficiency (48.53%) and gain (-1.38dBi) are comparable to antennas of much larger dimensions. A physics-based circuit model is developed for this FICA to assist system level design at the earliest stage, including optimization of the antenna performance. An antenna and low noise amplifier (LNA) co-design method is proposed and proven to be valid to design low power LNAs with the very low noise figure of only 1.5dB. To reduce receiver power consumption, this dissertation proposes a novel LNA active device and an input/ouput passive matching network optimization method. With this method, a power efficient high voltage gain cascode LNA was designed in a 0.13um CMOS process with only low quality factor inductors. This LNA has a 3.6dB noise figure, voltage gain of 24dB, input third intercept point (IIP3) of 3dBm, and power consumption of 1.5mW at 1.0V supply voltage. Its figure of merit, using the typical definition, is twice that of the best in the literature. A full low power receiver is developed with a sensitivity of -58dBm, chip area of 1.1mm2, and power consumption of 2.85mW

Proposed evolution technologies for Bluetooth

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Towards low power radio localisation

This work investigates the use of super-resolution algorithms for precision localisation and long-term tracking of small subjects, like rodents. An overview is given of a variety of techniques for positioning in use today, namely received signal strength, time of arrival, time difference of arrival and direction of arrival (DoA). Based on the analysis, it is concluded that the direction finding signal subspace based techniques are most appropriate for the purposes of our system. The details of the software defined radio (SDR) antenna array testbed development, build, characterisation and performance evaluation are presented. The results of direction finding experiments in the screened anechoic chamber emulating open-space propagation are discussed. It is shown that such testbed is capable of locating sources in the vicinity of the array with high precision. It can estimate the DoAs of more simultaneously working transmitters than antennas in the array, by employing spread spectrum techniques, and readily accommodates very low power sources. Overall constraints on the system are such that the operational range must be around 50 – 100 m. The transmitter must be small both volumetrically and in terms of weight. It also has to be operational over an extended period of around 1 year. The implications of these are that very small antennas and batteries must be used, which are usually accompanied by very low transmission efficiencies and tiny capacities, respectively. Based on the above, the use of ultra-low power oscillator transmitters, as first cut prototypes of the tag, is proposed. It is shown that the Clapp, Colpitts, Pierce and Cross-coupled architectures are adequate. A thorough analysis of these topologies is provided with full details of tag and antenna co-design. Finally the performance of these architectures is evaluated through simulations with respect to power output, overall efficiency and phase noise.Open Acces

Design of zigbee transmitter for IEEE 802.15.4 standrad

ZigBee is a standard defines a set of communication protocols for low-data-rate short-range wireless networking. ZigBee-based wireless devices operate in 868 MHz, 915 MHz, and 2.4 GHz frequency bands. The maximum data rate is 250 K bits per second. ZigBee is mainly for battery-powered applications where low data rate, low cost, and long battery life are main requirements. This thesis explores low power RFIC design for various blocks in Zigbee Transmitter. Zigbee RFTransmitter Comprises of Low Pass Filter, Variable Gain Amplifier, Up conversion Mixer and Power Amplifier. The proposed VGA is characterized by a wide range of gain variation The single-stage VGA is designed in UMC 0.18-u m CMOS technology and shows the maximum gain variation of 62 dB. The VGA dissipates 630 uA from 1.8-V supply while occupying (250 μm x 167.3 μm) of chip area. A low-voltage low-power and high linearity up-conversion mixer, designed in UMC 0.18-um RFCMOS technology is proposed to realize the transmitter front-end in the frequency band of 2.45 GHz. The proposed mixer can convert a 5 MHz intermediate frequency (IF) signals to a 2.45GHz RF signals, with a local oscillator at 2.45GHz. Simulation results demonstrate that at 2.45GHz, the circuit provides -11.30dB of conversion gain and the input-referred third-order intercept point (IIP3) of 35.16 dBm, output-referred third order intercept point(OIP3) of 12.88 dBm while drawing only 10mA for the mixer core under a supply voltage of 1.8 V. A low power Differential class A power amplifier is designed in the UMC 0.18um RFCMOS technology. The class A power amplifier provides 0 dBm output power with a power-added efficiency (PAE) of 22% and Power Gain of 10dB with 1.8V supply voltage. The dc power consumption is only 4.5mW. And all these blocks were integrated and simulated using Cadence© SpectreRF simulator in UMC-0.18um Mixed Signal CMOS RF models for the best simulation results

Bluetooth Wireless Technology: A milestone in ICT

This article summarizes the Bluetooth technology &#8211; a type of Wireless Personal Area Network (WPAN) with emphasis on the pivotal role of Bluetooth enabled devices in ICT. The areas of application of Bluetooth technology, itssecurity, basic design and architecture, and likely future trends in its applications are also discussed with a view to highlighting its major significance. Bluetooth was compared with other wireless communications technologies specifically Infrared Data Association (IrDA) and Wireless Fidelity (Wi-Fi&#174;) showing their dissimilarities and, above all, the advantages of Bluetooth wireless protocol over the other wireless technologies which have made it a topic of discourse in ICT are discussed

Noise-based Transmit Reference Modulation:A Feasibility Analysis

Wireless sensor networks (WSNs) receive huge research interest for a multitude of applications, ranging from remote monitoring applications, such as monitoring of potential forest fires, floods and air pollution, to domestic and industrial monitoring of temperature, humidity, vibration, stress, etc. In the former set of applications, a large number of nodes can be involved which are usually deployed in remote or inaccessible environments. Due to logistic and cost reasons, battery replacement is undesired. Energy-efficient radios are needed, with a power-demand so little that batteries can last the lifetime of the node or that the energy can be harvested from the environment. Coherent direct-sequence spread spectrum (DSSS) based radios are widely employed in monitoring applications, due to their overall resilience to channel impairments and robustness against interference. However, a DSSS rake receiver has stringent requirements on precise synchronization and accurate channel knowledge. To obviate the complexity of a coherent DSSS receiver, particularly for low data rate sensor networks, a DSSS scheme that has fast synchronization and possibly low power consumption, is much desired. In this regard, this thesis studies a noncoherent DSSS scheme called transmit reference (TR), which promises a simple receiver architecture and fast synchronization. In traditional TR, the modulated information signal is sent along an unmodulated reference signal, with a small time offset between them. In this thesis, we present and investigate a variant of TR, called noise-based frequency offset modulation (N-FOM), which uses pure noise as the spreading signal and a small frequency offset (instead of a time offset) to separate the information and reference signals. The detection is based on correlation of the received signal with a frequency-shifted version of itself, which collects the transmitted energy without compromising the receiver simplicity. Analytical expressions on performance metrics, supplemented by simulation results, improve understanding of the underlying mechanisms and provide insights into utility of N-FOM in low-power WSNs. In point-to-point line-of-sight (LOS) communication, it was observed that the communication scheme has a minimal utility. The energy-detector type of receiver mixes all in-band signals, which magnifies the overall noise. Particularly, the self-mixing of the transmitted signal also elevates the noise level, which increases with a further increase in the received signal energy. Therefore, for a fixed set of system parameters, the performance attains an asymptote with increasing transmission power. The phenomenon also establishes a non-monotonic relation between performance and the spreading factor. It was observed that a higher spreading factor in N-FOM is beneficial only in a high-SNR regime. After developing an understanding of the performance degrading mechanisms, few design considerations are listed. It is found that a suitable choice of the receiver front-end filter can maximize the SNR. However, the optimal filter depends on received signal and noise levels. A practically feasible – albeit suboptimal – filter is presented which gives close to the optimal performance. Next, timing synchronization is considered. The implications of synchronization errors are analyzed, and a synchronization strategy is devised. The proposed synchronization strategy has little overhead and can be easily implemented for symbol-level synchronization. The N-FOM LOS link model is extended to assess the performance degradation due to interference. Performance metrics are derived which quantify the effects of multiple-user interference, as well as that from external interferers, such as WiFi. Since the correlation operation mixes all in-band signals, the total interfering entities are quadratically increased. The research shows the vulnerability of N-FOM to interference, which makes it optimistic to operate in a crowded shared spectrum (such as the ISM 2.4\,GHz band). We also observe an upper limit on the number of mutually interfering links in a multiple access (MA) network, that can be established with an acceptable quality. The scheme is further investigated for its resilience against impairments introduced by a dense multipath environment. It is observed that despite the noise enhancement, the N-FOM system performs reasonably well in a non-line-of-sight (NLOS) communication. The detection mechanism exploits the multipath channel diversity and leads to an improved performance in a rich scattering environment. An analytical expression for outage probability is also derived. The results indicate that a healthy N-FOM link with very low outage probability can be established at a nominal value of the received bit SNR. It is also found that the choice of the frequency offset is central to the system design. Due to multiple practical implications associated with this parameter, the maximum data rate and the number of usable frequency offsets are limited, particularly in a MA NLOS communication scenario. The analysis evolves into a rule-of-thumb criterion for the data rate and the frequency offset. It is deduced that, due to its limited capability to coexist in a shared spectrum, N-FOM is not a replacement for coherent DSSS systems. The scheme is mainly suited to a low data rate network with low overall traffic, operating in an interference-free rich scattering environment. Such a niche of sensor applications could benefit from N-FOM where the design goal requires a simple detection mechanism and immunity to multipath fading

COMPLEX PULSE FORMING TEACHNIQUE USING AM DETECTOR TYPE CIRCUITRY AND THE APPLICATION OF CDMA TO RFID FOR THE SIMULTANEOUS READING OF MULTIPLE TAGS

A novel complex ultra wideband RF pulse forming technique has been implemented in this research, using the coefficients derived from discrete Fourier transform of a virtual pulse train. Incorporated in this technique is a multiple frequency communication systems designed such that transmitter receiver proximity and the fading effect of the individual frequencies make part of a corresponding modulation technique. A code division multiple access (CDMA) application to RFID to greatly reduce read time, while at the same time eliminating inter tag interference, has been investigated with the analysis of a typical cart aisle scenario. With the current rate of growth of inventory world wide there is a tremendous need for more efficient method of data gathering, data storage, and data retrieval. In this dissertation, the application of the CDMA RFID technology has been analyzed to demonstrate the potentials of integrating the RFID technology to the EPC global numbering system