GHz Operating Frequency Research Articles

A Floating-Body Transistor-Based Power Amplifier for Sub-6-GHz 5G Applications in SOI CMOS 130-nm Process

A floating-body transistor based two stages power amplifier (PA) with lateral NPN based bandgap voltage reference (BVR) is implemented in a 130 nm Silicon-On-Insulator (SOI) CMOS process for sub-6GHz 5G applications. Floating-body (FB) transistors instead of traditional body-contacted (BC) transistors have been adopted in driver stage and power stage amplifiers of the proposed PA. On-chip input and output transformer baluns (TB) are customized designed for this PA which can realize impedance matching. Split push-pull structure is adopted in both driver stage and power stage with inter-stage matching networks. Incorporating bonding wire multi-physics models into input and output matching and power gain temperature compensation, the proposed PA can achieve maximum 25.6 dB power gain, 22.2 dBm output power and 28% power added efficiency (PAE) at 1 dB compression point (OP-1dB). The 3 dB bandwidth of the proposed PA is from 4.3 GHz to 6.4 GHz and the core size is 0.59 mm2. When the proposed PA is used for IEEE 802.11ac application and measured at VHT80 MCS9 (80MHz, 256-QAM), it can achieve 21.4 dBm output power and 24.8% PAE at 5.5 GHz operating frequency with −36 dB error vector magnitude (EVM).

Radar System for Detecting Respiration Vital Sign of Live Victim Behind the Wall

The presence of an obstacle in detecting respiration vital signs using a radar system does not only exhibit attenuation and phase shift effects on the radar signal but also causes additional beat frequencies to appear beside those from the target. When a conventional FMCW radar system detects the peak of the received signal spectrum as a beat frequency, this will give an error of detection. The respiratory vital signs will then be undetectable. A method to overcome this obstacle problem is needed. Therefore the implementation of the FMCW radar system in detecting respiratory vital signs behind the wall can be realized. In this paper, a method to deal with the previously mentioned problem is proposed. The proposed method consists of a method for identifying the obstacle response. Then the results are used to eliminate the beat frequency that arises from the obstacle structure, and therefore the signal to clutter ratio (SCR) can be improved. Furthermore, the method is combined with the phase detection method, which is applied to extract the Doppler response related to the target respiratory vital signs. The weighting process by elaborating cross correlation is also employed for minimizing clutter from other objects reflection under debris. A laboratory experiment by developing an FMCW radar system with a 24 GHz frequency operation was performed in this research. The proposed detection method was elaborated in the post-processing of the radar system. The experiment result demonstrates that the proposed method is capable of eliminating the effect of the wall and successfully extracting the respiration vital sign pattern.

Design of CPW-Fed Conformal T-Shaped Flexible Patch Antenna With Slits for Biomedical Applications

In this paper, a conformal T-shaped flexible patch antenna is designed for biomedical applications. The proposed antenna designed using to resonate at 2.45 GHz operating frequency at ISM band. The proposed antenna operates in free space and muscle tissue. The proposed T-shaped patch antenna in free space resonates at 2.47GHz operating frequency with a bandwidth of 300MHz (2.45GHz and 2.75GHz).The antenna implanted in muscle tissue operates at 2.47GHz frequency with a bandwidth of 600MHz (2.25GHz – 2.85GHz). The return loss of -13.04dB is observed for T-shaped patch antenna in free space and the return loss for the antenna implanted in human tissue is -20.6dB respectively. The proposed flexible conformal patch antenna is compact in size, efficient in functioning, safe, and can effectively work within specified medical frequency bands.

A 1-to-3 GHz 5-to-512 Multiplier Adaptive Fast-Locking Self-Biased PLL in 28 nm CMOS

Based on a self-biased architecture, this paper presents a novel adaptive fast-locking, wide operating range and low-jitter phase-locked loop (PLL). A current injection and adaptive bandwidth technology with minimum area overhead is employed to speed up the loop equilibrium acquisition process, without any adverse impact on the steady-state loop dynamics and the jitter performance. The proposed start-up circuit resets the loop to an appropriate initial state in order to shorten the initial ramp-up interval of the voltage-controlled oscillator (VCO), also resulting in cutting down the pull-in time. In addition, a proportional factor is introduced to give some kind of flexibility in the circuit design optimization. The proposed adaptive fast-locking self-biased PLL (AFL-SPLL) is designed and realized in a prototype based on TSMC 28 nm CMOS process, having a supply voltage of 0.9 V and an area of 0.0281 mm2. This PLL demonstrates a tuning range of 1 to 3 GHz and power consumptions from 0.91 mW at 1 GHz to 4.6 mW at 3 GHz operating frequency. The experimental results show that the capture process has been accelerated by up to 84.7% over large division ratios, yet the capture performance did not deteriorate at all for small division ratios. Meanwhile, the circuit implementation gave almost no area increase and yet achieved a reduction in the lock-in time of about 6.5 times, namely from 23.5 μs (without the adaptive locking) to only 3.6 μs (with the adaptive locking) on the maximum operation frequency condition of 3 GHz.

A Novel 65 nm Active-Inductor-Based VCO with Improved Q-Factor for 24 GHz Automotive Radar Applications.

The inductor was primarily developed on a low-voltage CMOS tunable active inductor (CTAI) for radar applications. Technically, the factors to be considered for VCO design are power consumption, low silicon area, high frequency with reasonable phase noise, an immense quality (Q) factor, and a large frequency tuning range (FTR). We used CMOS tunable active inductor (TAI) topology relying on cascode methodology for 24 GHz frequency operation. The newly configured TAI adopts the additive capacitor with the cascode approach, and in the subthreshold region, one of the transistors functions as the TAI. The study, simulations, and measurements were performed using 65nm CMOS technology. The assembled circuit yields a spectrum from 21.79 to 29.92 GHz output frequency that enables sustainable platforms for K-band and Ka-band operations. The proposed design of TAI demonstrates a maximum Q-factor of 6825, and desirable phase noise variations of −112.43 and −133.27 dBc/Hz at 1 and 10 MHz offset frequencies for the VCO, respectively. Further, it includes enhanced power consumption that varies from 12.61 to 23.12 mW and a noise figure (NF) of 3.28 dB for a 24 GHz radar application under a low supply voltage of 0.9 V.

Steering of Beam Using Cylindrical Arrangements in a Metallic Parallel Plates Structure Operating over Ku-Band

A novel flat beam steering prototype based on the specific arrangement of a cylindrical unit cell is designed, manufactured and tested. The wideband and broad scanning capability is demonstrated at the Ku-band. We have considered two configurations, first with circular rings (CR) of the defined permittivity values for respective radial distance from the center of the aperture, second with cylindrical rods that shall be placed on a respective CR, which mimics the defined permittivity. The structure is generated from Vero CMYK full color wax, which utilizes the Multijet 3D printing method. The proposed prototype is designed in the operating frequency of 12 GHz (λ = 25 mm) and separation distance between the two parallel plates are maintained at 12.5 mm (0.5λ) for the TE10 mode of operation. The diameter of the two parallel plates and the proposed structure is of 100 mm (4λ) where the radius of cylinders varies from 0.5 to 3.5 mm and corresponding relative permittivity varies from 0.6687 to 2.4395. The overall height of the structure is 12.5 mm and is placed between two parallel plates. The minimum separation distance is maintained between the proposed structure and the feed WR-75 waveguide. Irises effect is performed to obtain impedance matching in the operating frequency bands. Beam steering of the radiated waves is observed for relative rotation angles of 0∘, 30∘, 45∘, 75∘ and 90∘ of the WR-75 waveguide along the edge of parallel plates. The overall proposed system weighs 179 g, which signifies the light weight characteristics. Moreover, the proposed structure shows low return loss over 10 GHz to 15 GHz operating frequency band.

2x2 Array Microstrip Patch Antenna Designing and Validation with Artificial Neural Networks

A novel and successful method for RF, microwave modelling, and antenna design has gained attention: computational modules based on neural networks. The behavior of active or passive components or circuits can be taught to neural networks. The design of a microstrip patch antenna utilizing an artificial neural network (ANN) is discussed in this research. Computer Simulation Technology (CST) is used to establish the antenna's size and characteristics in order to create a successful ANN model. The feed-forward back-propagation neural network and Levenberg Marquardt optimization algorithm are used to model the antenna design. High-Frequency Structure Simulator (HFSS) software, operating at 2.4 GHz, is used to build the initial microstrip patch (ISM band).A 2.4GHz operating frequency is used to create a 2*2 microstrip planar array. A variety of neural networks are evaluated and trained to produce the most ideal results after generating and modelling discoveries using HFSS simulation software and the Finite Difference Time Domain (FTDT) approach. In this research, neural networks are utilized. In order to identify the most ideal solution, optimization is performed using a radial basis function neural network (RBF NN) and a feed-forward backpropagation approach.

Wi-Fi Antenna Design For E-Health Kit Based Biotelemetry Module

In rapidly developing technology, most of engineering applications need to be done remotely. An antenna is needed to transmit the values ​​received as a result of these remote studies. The antenna type that is more suitable to use in line with this need is the Wi-Fi antenna. Although this antenna is low in cost, it provides benefits to the user by using a good band. In this study, a Wi-Fi antenna design at 2.4 GHz frequency for use in the E-Health kit-based biotelemetry module is discussed. In this designed antenna, FR-4 substrate with dielectric coefficient of 4.3 is used. In the ground and patch parts, copper was used as the material. The return loss is 13.54 dB at 2.4GHz operating frequency with the gain value of 2.75 dBi. It was aimed to use this antenna as a Wi-Fi antenna in the E-Health kit-based biotelemetry module.

Design and Interpretation of Microstrip Patch Antenna Operating at 2.4GHz for Wireless WI-FI Application

With the renewed and changing technology in recent years, wireless communication has increased its importance in engineering, communication, transportation and almost every field. In this study, a Wi-Fi antenna with 2.4 GHz operating frequency, which is one of the leading studies of antenna technology, which can be used in wireless communication technology, has been designed. Wi-Fi antenna is very important for this technology, which has become indispensable for everyone today. To design the Wi-Fi antenna, the operating frequency specified in the IEEE 802.11 standards has been taken into account. While choosing the antenna model, micro-strip antenna was preferred due to its geometry, lightness, low production cost and compactness. While designing the antenna, CST Microwave Studio program was used and necessary measurements were made. While designing the antenna, FR-4 substrate with a dielectric coefficient of 4.3 and a thickness of 1.6 mm was used. Copper was used as the material for the ground and patch parts. As a result of the design, most of the intended goals were achieved. Graphs were analyzed from the CST microwave studio program. When the required S parameter value is examined; The antenna obtained as a result of this study operates in the 2.26 GHz-2.38 GHz band range, which is the targeted frequency of 2.4 GHz. The Wi-Fi antenna obtained in this study; return loss value is 25.90dB and gain value is 4.66 dBi. These results are acceptable according to the standards

Compact Dual Band and Dual Polarized CPW-Fed Triangular Shaped Wearable Antenna for ISM band Applications

ABSTRACT A coexisting compact dual coplanar waveguide (CPW)-fed dual-band and dual-polarized triangular-shaped wearable antenna (TSWA) is proposed for 2.45 GHz and 5.8 GHz ISM (Industrial, Scientific and Medical) frequency bands. The proposed antenna of area 722 mm2 is fabricated on polyimide substrate (thickness of 1.6 mm and relative permittivity of 3.5). The two identical inverted-L-shaped feed stubs are employed orthogonally in wide triangular slot to provide both horizontally and vertically polarized radiations in both ISM bands. An additional Y-shaped copper strip is introduced to isolate the two inverted-L-shaped feed stubs in order to achieve higher isolation in both 2.45 and 5.8 GHz operational frequency bands. The proposed TSWA achieves similar −10 dB impedance bandwidths of 21.7% (2.30 ̶ 2.86 GHz) and 14.26% (5.60 ̶ 6.46 GHz) respectively for dual-polarized radiations along with more than 20 dB isolation in both 2.45 and 5.8 GHz ISM bands. The effect of human loading on performance of proposed TSWA is also studied. The proposed antenna is designed, fabricated, and tested. The simulated results are verified and validated with measured ones and thus, makes it suitable for wearable ISM bands applications.

Wireless Energy Harvesting Using Rectenna Integrated with Voltage Multiplier Circuit at 2.4 GHz Operating Frequency

In this paper, we utilized villared rectifier technique to harvest wireless energy to overcome previously used RF-WEH rectenna. Our design focuses mainly on a multiple-stage Villard voltage multiplier model to rectify the output voltage of the rectenna and transferred it to a dc load. As a starting point, optimization and parameter analysis offer a novel and small antenna for the 2.45 GHz ISM band that precisely matched. Moreover, the fabricated prototype has measured and simulated results have confirmed the antenna’s accuracy in the reflection coefficient. Second, a highly efficient antenna may effectively harvest the electrical energy by combining with the two-stage voltage multiplier circuit presented at the ISM band. Furthermore, the proposed rectenna has the optimum performance compared to state of art rectennas in terms of efficiency, power range, and impedance bandwidth showing pronounced achievement and increasing the DC output power significantly. The prototype is fabricated and experimentally tested to confirm the concept. Measurement results show that the proposed rectenna can be used for RF energy harvesting applications.

Phase Noise Measurements for L-Band Applications at Attosecond Resolution

This article summarizes theoretical and technical limitations when applying carrier-suppression interferometer (CSI) methods for precision phase-noise measurements at attosecond resolution. The CSI setup reported here outperforms conventional down-mixing methods by more than two orders of magnitude. For phase noise measurements at 1.3 GHz operation frequency, a detection floor of <inline-formula> <tex-math notation="LaTeX">$\mathscr {L}={-205}\,\,{\text {dBc/Hz}}$ </tex-math></inline-formula> and an excellent time resolution of 10.76 as within an offset frequency range from 40 Hz to 1 MHz have been achieved without the usage of cross correlation or power recycling techniques. Measurement setup resolution limits, calibration methods, and effects of transmission line group delays are reported. Phase shifters and attenuators in the CSI were identified as key components. Different phase shifter technologies based on passive switches, varactor diodes, and capacitors were investigated. The presented research can be used in future in combination with conventional receiver techniques and enhances the state of the art of phase noise measurements to attosecond resolution and above.

Design of an Ultrawideband Circularly Polarized Printed Crossed-Dipole Antenna Based on Genetic Algorithms for S-Band CubeSat Applications

As in any satellite, onboard antennas for CubeSats are crucial to establish communication with ground stations or other satellites. According to its application, antennas must comply with standardized requirements related to size, bandwidth, operating frequency, polarization, and gain. This paper presents an ultrawideband circularly polarized two-layer crossed-dipole microstrip antenna for S-band CubeSat applications using genetic algorithms optimization tools included in the 3D electromagnetic simulation software Ansys HFSS. The antenna is constructed on a 10 × 10 cm Cuclad-250 substrate with a back copper flat plane, located at λ/4 at 2.25 GHz operating frequency. The backplane with the exact substrate dimensions improves gain and reduces inside satellite radiation. Measured bandwidth defined by S11 at a −10 dB was higher than 1835 MHz with S11 = −24.68 dB at the central frequency of 2.25 GHz, while measured VSWR at the same frequency was 1.124. At 2.25 GHz, the maximum measured gain and the minimum measured axial ratio in the broadside direction were found to be 6 dBi and 0.22 dB, respectively. There are antenna simulations and measurements, as long as its fabrication guarantees application requirements that make it ready for prespace testing.

Antenna Design and Fabrication with Circular Microstrip Patch: A Review

The paper presents a review on antenna designing and fabrication techniques with Microstrip Patch (MSP) development. The requirements of MSP are remote controlling, mobile communication, space communication and all wireless communication areas. Aim of this development is to provide a new approach of the designing and simulation of circularMSP for 5.8 GHz operating frequency. CST MICROWAVE STUDIO (MWS) facilitates the quick and accurate analysis of high frequency (HF) antennas which gives the responses and results before fabrication of actual patch with complete technology for 3D EM. FR-4 glass epoxy material board is used for fabrication which is admired and adaptable highpressure thermoset plastic laminate grade with superior strength to weight ratios. Circular MSP is easy to fabricate, portable, lightweight and low cost antenna. N9923A Field Fox RF VNA (Vector Network Analyser) were used for studying and testing all the parameters of fabricated MSP.

A Sub-6G SP32T Single-Chip Switch with Nanosecond Switching Speed for 5G Applications in 0.25 μm GaAs Technology

This paper presents a single-pole 32-throw (SP32T) switch with an operating frequency of up to 6 GHz for 5G communication applications. Compared to the traditional SP32T module implemented by the waveguide package with large volume and power, the proposed switch can significantly simplify the system with a smaller size and light weight. The proposed SP32T scheme utilizing tree structure can dramatically reduce the dc power and enhance isolation between different output ports, which makes it suitable for low-power 5G communication. A design methodology of a novel transmission (ABCD) matrix is proposed to optimize the switch, which can achieve low insertion loss and high isolation simultaneously. The average insertion loss and the isolations are 1.5 and 35 dB at 6 GHz operating frequency, respectively. The switch exhibits the measured input return loss which is better than 10 dB at 6 GHz. The 1 dB input compression point of SP32T is 15 dBm. The prototype is designed in 5 V 0.25 μm GaAs technology and occupies a small area of 12 mm2.

Graded refractive index metamaterial for enhanced far-field wireless power transfer efficiency in S-band

A graded refractive index metamaterial (MM) exhibits a magnetic dipole designed and demonstrated experimentally for 2.45 GHz operating frequency. The system efficiency of the far-field wireless power transfer technique increased to 32.6% with MM. With 16° reduction in half power beamwidths, 9.78 dBm is received at 1 m with 30 dBm input when MM is placed at an optimum distance of 2.5λ0 from transmitting antenna aperture. The method is studied experimentally, and results are compared with the Friis transmission equation, thus validating experimental and theoretical analysis. The system efficiency is always higher than the system with no MM, and hence the proposed method is suitable for long-range wireless power transfer applications maximizing the theoretical power received.

Investigation of PVT-Aware STT-MRAM Sensing Circuits for Low-VDD Scenario.

Spintronic based embedded magnetic random access memory (eMRAM) is becoming a foundry validated solution for the next-generation nonvolatile memory applications. The hybrid complementary metal-oxide-semiconductor (CMOS)/magnetic tunnel junction (MTJ) integration has been selected as a proper candidate for energy harvesting, area-constraint and energy-efficiency Internet of Things (IoT) systems-on-chips. Multi-VDD (low supply voltage) techniques were adopted to minimize energy dissipation in MRAM, at the cost of reduced writing/sensing speed and margin. Meanwhile, yield can be severely affected due to variations in process parameters. In this work, we conduct a thorough analysis of MRAM sensing margin and yield. We propose a current-mode sensing amplifier (CSA) named 1D high-sensing 1D margin, high 1D speed and 1D stability (HMSS-SA) with reconfigured reference path and pre-charge transistor. Process-voltage-temperature (PVT) aware analysis is performed based on an MTJ compact model and an industrial 28 nm CMOS technology, explicitly considering low-voltage (0.7 V), low tunneling magnetoresistance (TMR) (50%) and high temperature (85 °C) scenario as the worst sensing case. A case study takes a brief look at sensing circuits, which is applied to in-memory bit-wise computing. Simulation results indicate that the proposed high-sensing margin, high speed and stability sensing-sensing amplifier (HMSS-SA) achieves remarkable performance up to 2.5 GHz sensing frequency. At 0.65 V supply voltage, it can achieve 1 GHz operation frequency with only 0.3% failure rate.

Design and Analysis of Metamaterial based-check board AMC Backed EBG Antenna for Body Placement Applications

In this paper a compact EBG antenna with Artificial Magnetic Conductor (AMC) is proposed for on body applications. The proposed antenna is designed with single SRR (split ring resonator) and double SRR to differentiate the performance of the proposed antenna. The proposed EBG antenna bending analysis is performed at different angles on human body to attain good radiation characteristics. The footprint of proposed antenna is of 0.2λ0*0.24λ0mm2 and AMC with dimension of 0.48λ0*0.48λ0 mm2.The proposed antenna is obtained good return loss and radiation characteristics when EBG antenna is placed on the human leg with an angle of 300 at corresponding operating frequencies 2.4GHz, 5.8GHz, 9GHz and 9.5GHz respectively. The obtained operating frequencies cover wireless applications such as GPS, ISM, and Radar and satellite communications. The proposed EBG antenna is obtained with high gain 7.05dBi at 9.5GHz operating frequency. The surface current distributions are obtained for the proposed antenna is of 137A/m. Good isometric radiation patterns are observed for the proposed antenna. The SAR analysis is performed when the EBG antenna is placed on the human leg at an angle of 30degree is of 1.23W/kg.

A novel CMOS hexaferrite circulator with 25 GHz operating frequency

A novel CMOS hexaferrite circulator with a Y-junction structure is designed and fabricated, which is compatible with standard CMOS technology. The spin-coating approach is adopted during the fabrication, in which the photoresist is mixed with nano-hexaferrite powder for preparation of a magnetic thin film in the device. Compared with the traditional circulator with an external permanent magnet for operation, the novel circulator can utilize the spin-coating magnetic film and is compatible with CMOS technology. The remanent magnetization of the adopted hexaferrite thin film can provide the required magnetic field for reciprocity properties. The optimization of impedance matching and the improvements in the related parameters are demonstrated on the novel CMOS circulator. The CMOS circulator exhibits the merits of small volume and easy integration while keeping its promising non-reciprocity properties. The fabrication is conducted based on the standard 180-nm CMOS technology. S-parameter measurements on the circulator show that the device has an isolation of 20 dB over 520 MHz bandwidth at 26.2 GHz. The minimum insertion loss is 1.81 dB. The novel CMOS-compatible circulator has potential application in 5G wireless communication systems.

Wearable transceiver design & breast tumour’s coverage diagnostic by composites

An EF shaped microstrip slots with 3 × 3 array pattern has stitched on wearable textile woven has presented in this research. These prototypes have examined with biological equivalent content of composite model to be determined the depth of the cancer in the cancerous organ. It has investigated the breast cancer application, which is used in the microwave imaging system. The both woven modules offered the 5.33 GHz operational frequency and has achieved from Agilent N99917A microwave analyzer. These wearable modules had no radiation at all on the human body. It has determined the depth of cancerous tissues presented in the cancerous organ with the help of velocity of propagation, distance between the cancerous organ and transceiver antenna, dielectric strength and travelling time of scattered responses respectively. Therefore, these scattered responses have obtained from the cancerous organ under Debye test bed. Hence, the numerical value of depth and spreading the coverage of depth in cancerous organ, which is validated under existing Debye test beds.