Browsing by Author "Mayeda, Jill C. (TTU)"
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Item A Broadband Millimeter-Wave 5G Low Noise Amplifier Design in 22 nm Fully-Depleted Silicon-on-Insulator (FD-SOI) CMOS(2023) Ouyang, Liang-Wei (TTU); Mayeda, Jill C. (TTU); Sweeney, Clint (TTU); Somasundaram, Gokul (TTU); Lie, Donald Y. C. (TTU); Lopez, Jerry (TTU)This paper presents a design of a broadband millimeter-wave (mm-Wave) low noise amplifier (LNA) designed in a 22 nm fully-depleted silicon-on-insulator (FD-SOI) CMOS technology. The post-layout parasitic extracted (PEX) simulations suggest the LNA has a 3-dB bandwidth (BW) from 16.9 – 41.8 GHz and a fractional bandwidth (FBW) of 84.8 %, covering the key frequency bands within the mm-Wave 5G FR2 band, with its noise figure (NF) ranging from 2.9 – 4.1 dB, and its input-referred 1-dB compression point (IP1dB) of −19.4 dBm at 28 GHz with 15.8 mW DC power consumption. Using the FOM (figure-of-merit) developed from Ref. [1] for broadband LNAs (FOM ≡20×log((Gain[V/V]×BW[GHz])/(PDC[mW]×(F−1)), this LNA achieves a competitive FOM among reported mm-Wave LNAs in literature [1–7].Item A Feasibility Study of Remote Non-Contact Vital Signs (NCVS) Monitoring in a Clinic Using a Novel Sensor Realized by Software-Defined Radio (SDR)(2023) Liu, Yang (TTU); Sweeney, Clint (TTU); Mayeda, Jill C. (TTU); Lopez, Jerry (TTU); Lie, Paul E. (TTUHSC); Nguyen, Tam Q. (TTU); Lie, Donald Y.C. (TTU)The COVID-19 outbreak has caused panic around the world as it is highly infectious and has caused about 5 million deaths globally. A robust wireless non-contact vital signs (NCVS) sensor system that can continuously monitor the respiration rate (RR) and heart rate (HR) of patients clinically and remotely with high accuracy can be very attractive to healthcare workers (HCWs), as such a system can not only avoid HCWs’ close contact with people with COVID-19 to reduce the infection rate, but also be used on patients quarantined at home for telemedicine and wireless acute-care. Therefore, we developed a custom Doppler-based NCVS radar sensor system operating at 2.4 GHz using a software-defined radio (SDR) technology, and the novel biosensor system has achieved impressive real-time RR/HR monitoring accuracies within approximately 0.5/3 breath/beat per minute (BPM) on student volunteers tested in our engineering labs. To further test the sensor system’s feasibility for clinical use, we applied and obtained an Internal Review Board (IRB) approval from Texas Tech University Health Sciences Center (TTUHSC) and have used this NCVS monitoring system in a doctor’s clinic at TTUHSC; following testing on 20 actual patients for a small-scale clinical trial, we have found that the system was still able to achieve good NCVS monitoring accuracies within ~0.5/10 BPM across 20 patients of various weight, height and age. These results suggest our custom-designed NCVS monitoring system may be feasible for future clinical use to help combatting COVID-19 and other infectious diseases.Item Effective Digital Predistortion (DPD) on a Broadband Millimeter-Wave GaN Power Amplifier Using LTE 64-QAM Waveforms(2023) Somasundaram, Gokul (TTU); Mayeda, Jill C. (TTU); Sweeney, Clint (TTU); Lie, Donald Y.C. (TTU); Lopez, Jerry (TTU)We demonstrate in this work effective linearization on a millimeter-wave (mm-Wave) broadband monolithic gallium nitride (GaN) power amplifier (PA) using digital predistortion (DPD). The PA used is a two-stage common-source (CS)/2-stack PA that operates in the mm-Wave 5G FR2 band, and it is linearized with the generalized memory polynomial (GMP) DPD and tested using 4G (4th generation) long-term-evolution (LTE) 64-QAM (quadrature amplitude modulation) modulated signals with a PAPR (peak-to-average power ratio) of 8 dB. Measurement results after implementing GMP DPD indicate considerable broadband improvement in the adjacent channel leakage power ratio (ACLR) of 16.9 dB/17.3 dB/16.5 dB/15.1 dB at 24 GHz/28 GHz/37 GHz/39 GHz, respectively, with a common average POUT of 15 dBm using a 100 MHz LTE 64-QAM input signal. At a fixed frequency of 28 GHz, the GaN PA after GMP DPD achieved signal bandwidth-dependent ACLR improvement and root-mean-square (rms) EVM (error vector magnitude) reduction using 20 MHz/40 MHz/80 MHz/100 MHz LTE 64-QAM waveforms with a common average POUT of 15 dBm. The GaN PA thus achieved very good linearization results compared to that in other state-of-the-art mm-Wave PA DPD studies in the literature, suggesting that GMP DPD should be rather effective for linearizing mm-Wave 5G broadband GaN PAs to improve POUT, Linear.