7-bit phase shifter using SiGe BiCMOS technology for X-band phased array applications

Phase array T/R modules achieve high performance with III-V technologies. However, the cost of III-V technologies is high. Recent developments in SiGe BiCMOS technology show us that III-V technology can be replaced with SiGe BiCMOS. Moreover, thanks to the integration of the CMOS, digitally controlled T/R modules can be realized with that technology. Power dissipation, area, and integration complexity can be reduced with SiGe BiCMOS technology. Also, the number of radiating elements and the cost of T/R module can be reduced with phase shifters with high phase resolution. In the light of these trends, this thesis presents a 7-bit low insertion-loss SiGe X-band (8-12 GHz) passive phase shifter, realized in IHP 0.25- m SiGe BiCMOS process. The phase shifter is based on high-pass/low-pass lter topology with a new proposed switching technique. This technique decreases the number of series switch by dividing each phase into 4 arms instead of two arms. Also, in this technique, instead of using two single pole switches consecutively, multiple pole switches are realized. Thanks to the IHP SiGe BiCMOS technology, isolated NMOSs are used which improve insertion-loss of the phase shifter. The overall phase shifter is composed of BALUN, SP4T, DP4T, 4P4Ts, and phase blocks to create a phase shift for achieving 7-bit phase resolution. The return loss of each state is better than 10 dB and the phase shifter has an average of 14.5 dB insertion loss. Minimum 1 RMS phase error is obtained at 10 GHz. RMS phase error is better than 6 at 9-11 GHz band. The phase shifter occupies an area of 6 mm2 and it has no DC power consumption. The thesis also summarizes the work that was contributed as part of the complete TR Module generation. These include active and passive gain equalizers that are utilized in the Module to generate desired slope in the receiver / transmitter chain

A 7-bit reverse-saturated SiGe HBT discrete gain step attenuator

In this study, the analysis, design and measured results of a fully integrated 7-Bit step attenuator implemented in a 0.25-μm Silicon-Germanium (SiGe) BiCMOS process technology, are described. The attenuator is designed based on delicately ordered and cascaded Π/T type attenuation blocks, which are comprised of series/shunt switches employing SiGe hetero-junction bipolar transistors (HBTs) with peak fT/fmax of 110/180 GHz. HBTs are employed as a series switch to decrease the insertion-loss of the attenuator. Moreover, to authors’ best knowledge, this is the first study presenting the effect of employing reverse-saturated HBTs as a shunt switch for each attenuation blocks. Thanks to this advancement, the highest input-referred 1-dB compression point (IP1dB) is reported for Si-based similar studies. This method also decreases the insertion-loss of the proposed attenuator. The measurements result in the state-of-the-art performance with 28.575 dB attenuation range by 0.225 dB gain steps while maintaining 7-bit amplitude resolution across 6.6 GHz to 12.8 GHz frequency band, where RMS phase error remains below 3.3∘ and insertion loss (IL) is less than 12.4 dB. The measured IP1dB of the attenuator is 13.5 dBm while drawing 8 mA from 3.3 V supply. The die occupies an area of 1.37 mm x 0.56 mm excluding pads

A tunable SiGe BiCMOS gain-equalizer for x-band phased-array RADAR applications

This paper presents a compact-size tunable gain-equalizer for X-Band Phased-Array RADAR applications in a 0.25μm SiGe BiCMOS technology. An isolated NMOS based variable resistance was used for the first time to tune the slope of the gain-equalizer. For NMOS, an isolated body created by a deep n-well was utilized to reduce insertion loss due to the substrate conductivity. Furthermore, the power-handling capability of the tunable gain-equalizer was improved thanks to the resistive body-floating technique. The designed tunable gain-equalizer operates in the frequency range from 8 to 12.5 GHz with a measured positive slope of 1 dB/GHz and 1 dB tunable slope. The effective chip area excluding the pads is 0.21 mm2, and the total area including pads is 0.31 mm2. To authors best knowledge, this study is the first tunable gain-equalizer in SiGe technology presented for X-band phased-array RADAR applications

Use of Micro-Cogeneration in Microgrids to Support Renewables

The use of renewable energy sources has experienced great development so as to meet energy demand. With the intention of increasing the utilization of the renewable energy sources near the demand side and compensate the fluctuation of the output power, the use of micro-cogeneration systems with solar (PV) and wind energy overcomes both technical and economic barriers. Micro-cogeneration-based hybrid PV/wind energy system can get stable power output. This new energy model also improves the power quality and significantly reduces the impact of power instability on the power network. In this study, the grid-connected hybrid PV/wind energy-based micro-cogeneration system is modeled and analyzed in detail. In order to test the performance analysis of the system, seven different scenarios are analyzed during the case studies. The analysis results show that the new energy model presents effective solutions to electrical power balance because of its properties such as safety, incombustible structure, and being eco-friendly. It is aimed at providing a broad perspective on the status of optimum design and analysis for the micro-cogeneration-based hybrid PV/wind energy system to the researchers and the application engineers dealing with these issues

Active positive sloped equalizer for x-band SiGe BiCMOS phased array applications

This work presents an active equalizer circuit with positive gain slope at X-Band (8 - 12 GHz). Compared to passive examples, the active equalizer realized better filter and impedance characteristics in frequency of interest with increased functionality for a single amplification stage. It achieved close to 10 dB of peak gain, a + 1.13 dB/GHz gain slope with 2.8 dB NF by utilizing cascode topology. The design reaches a -1.5 dBm input-referred compression point (input-P1dB) while consuming 46 mW of power. To the best of authors’ knowledge, the presented work achieves the best on-chip gain, a gain slope and NF performance in the literature as an equalizer that utilizes SiGe BiCMOS technology

A 5-13 GHz 6-Bit vector-sum phase shifter with+3.5 dBm IP1dB in 0.25-mu m SiGe BiCMOS

This paper presents a wideband vector-sum phase shifter (VSPS) with high phase resolution and high input-referered 1 dB compression point (IP1dB) which covers the full 360 degrees phase range with 5.6 degrees phase steps between 5-13 GHz in a commercial 0.25-mu m SiGe BiCMOS technology. A transformer balun and an RC polyphase filter (PPF) are implemented for inphase and quadrature phase (I/Q) reference vector generation while the desired phase states are generated by an adder stage where the amplitudes of the I/Q reference vectors are manipulated with digitally controlled variable gain amplifiers (VGAs). The measured root mean square (RMS) phase error of the VSPS is 7.8 dB. Thus, the VSPS achieves 6-bit phase resolution. IP1dB for the 1st state of the VSPS at 10 GHz is measured to be +3.5 dBm. Overall chip size of the VSPS IC is only 1.22x0.59 = 0.71 mm(2), excluding the RF and the DC pads

Comparing The Rate of Radiological and Clinical Adjacent Segment Degeneration After Simple Anterior Cervical Discectomy Versus Discectomy Plus Fusion

Objective: To evaluate and compare the radiological changes on adjacent mobile segments and clinical findings in patients having undergone single-segment simple anterior cervical discectomy versus discectomy plus intervertebral fusion.Material and Methods: Twenty-five patients were treated with discectomy plus fusion and 20 patients with simple discectomy. Clinical pictures of the patients were evaluated with ODOM criteria before and 1 year after operation, and their improvement rates were calculated. The disc heights of superior and inferior adjacent segments, superior and inferior foramen heights, superior and inferior end plate heights of superior and inferior adjacent segments, new osteophyte development, segmental angulation and loss of cervical lordosis were evaluated on cervical radiographies before and 1 year after operation.Results: Although there were new degenerative findings in adjacent mobile segments in all patients when preoperative and postoperative measurements were compared, these radiological findings did not translate into clinical findings. In the fusion group, radiological degeneration findings were seen more frequently statistically; however, clinical results were not different between the two groups. On the other hand, loss of lordosis was significantly more frequent in the simple discectomy group.Conclusion: Although adding fusion to single-segment anterior cervical discectomy caused more frequent radiological degenerative changes in adjacent segments after 1 year compared to simple discectomy, clinical results were similar. It was thought that longer follow-up was necessary to observe clinical adjacent segment disease that was expected to become more frequent because of excessive mobility due to fusion

A SiGe BiCMOS bypass low-noise amplifier for x-band phased array RADARs

This paper presents a bypass low noise amplifier (LNA) for X-band phased array applications in 0.25μm SiGe BiCMOS technology. The trade-off between gain and bypass modes is considered to achieve high gain as well as low noise figure for gain mode while maintaining reasonable insertion loss with high power handling capability in bypass mode. In gain mode, the LNA achieves a measured gain of 17-14.2 dB and a noise figure of 1.75-1.95 dB over the 8-12 GHz band while consuming 27.4mW of DC-power. The measured input-referred I-dB compression point (IP 1dB ) is -3.9 dBm at 10 GHz. When operating in bypass mode, the measured insertion loss is 6.5-5.95 dB over the entire X-band with the measured IP 1dB of 15.1 dBm at 10 GHz, and it dissipates only 1μW power. Thanks to the bypassing technique, an increase of about 19 dB is achieved for IP 1dB in bypass mode compare to the gain mode. The measured return losses are better than 10 dB for both operating modes over whole X-band. The effective chip area excluding the pads is 0.3 mm 2

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

4x1 Mimo compact half duplex RF T/R module with high resolution in 130 NM sige bicmos for 5G applications/

This thesis focuses on the design and implementation of a radio frequency (RF) integrated transmit/receive (T/R) module for the next-generation 5G communication. To achieve the performance requirements of the 5G communication, such as high data rate and low latency, new design methodologies are needed such as multipleinput and multiple-output (MIMO), and millimeter-wave (mm-wave) based circuits. Moreover, low power dissipation and low area are also essential performance requirements for the next-generation communication to decrease the cost of the system. One of the requirements of 5G is a data rate up to 25 Gb/s. In order to meet this requirement, the bandwidth of communication must be increased, which is possible with mm-wave circuitry. However, a higher attenuation in the atmosphere occurs in mm-wave frequency. In order to compensate for this attenuation, MIMO half-duplex phased arrays can be realized to create a beam-steering with a desired gain. This thesis presents four-element TX/RX circuits and a single-channel TRX for creating a beamformer for MIMO-based systems. Both ICs designed with SiGe BiCMOS technology for 5G applications specifically for 26 GHz. First, four-element TX and RX channels are realized to create a 5G communication scheme at the mm-wave frequencies. These four-channel elements are based on sub-blocks: low noise amplifier (LNA), power amplifier (PA), phase shifter (PS), attenuator (ATT), variable gain amplifier (VGA), Wilkinson combiner, and serial peripheral interface (SPI). The designed circuitry achieved a 6-b phase control and 4-b amplitude control. To the best of the authors’ knowledge, the designed module achieved the highest phase and amplitude resolution, along with the highest amplitude range, and the lowest RMS amplitude error in the literature. Moreover, the designed module achieved 15.5 dB RX gain, 25.5 dB TX gain, 4.5 dB NF, 9.5 dBm OP1dB, and 50 mW power consumption which are acceptable performances with respect to the state-of-the-art. Second, after realizing the four-element TX and RX channels, we realized that parameters such as, power consumption and area can be improved. These improvements will create a massive advantage while creating a phased array system. Also, we realized that we can increase the module’s functionality by increasing the phase and amplitude resolution and adding a self built-in test to check whether the channel is working or not. Single-channel TRX is implemented with higher phase and amplitude resolution and lower chip area and power consumption. To achieve the aforementioned performance, two new techniques were performed. First, to decide the mode of operation, conventional switch topology, asymmetric switches, and switchless LNA and PA are realized. Second, phase and amplitude will be adjusted with a single block for the first time. The current steering technique will be used for both phase and amplitude resolution in a single block. Since the asymmetric switch and switchless topology consume less area with lower insertion-loss performances and the vector modulator performs the phase and amplitude settings with the single block, the area and the power consumption of the overall module will be reduced. Based on the measurement results, the designed circuitry achieved 7-bit phase and 6-bit amplitude resolution, which corresponds to the highest phase and amplitude resolution in the literature. While achieving the highest phase and amplitude resolution, the lowest RMS phase and amplitude error are also achieved with a single block. Moreover, the designed circuitry achieved 19 dB gain in RX mode, 20 dB gain in TX mode, 5 dB NF, and 11.5 dBm OP1dB are also achieved, which are enough to create a 5G communication scheme