dBm Input Research Articles

Analysis of Facet-Loaded Rectangular DR-Rectenna Designs for Multisource RF Energy-Harvesting Applications

In this article, the characteristics of four spiral-facet structures are studied for RF energy-harvesting (RFEH) applications for increasing the harvesting power from the surrounding atmosphere. A rectangular dielectric resonance antenna (RDRA) is selected and placed above an FR4-epoxy substrate. Metallic rectangular spirals are then placed on the dielectric resonator (DR) surface to create resonances with insensitive polarization characteristics. The proposed spirals help provide wideband/multiband characteristics at 4.85, 5.0, 5.5, 5.8, and 6.25 GHz that covers 5G 4.9, WLAN 5.0, WLAN 5.5, Wi-Fi 5.8, and Wi-Fi 6E bands, respectively. The minimum gain achieved is 5 dBi in all possible configurations. A broadband rectifier circuit (4.67–7.0 GHz) with a staircase multistage transmission line matching network (MN) covering all resonant frequencies in various facet-loaded antenna configurations is proposed for RF-to-dc conversion purposes. The rectifier’s maximum power conversion efficiency (PCE) is achieved as 77.3% at a 13.5 dBm input power level, and the corresponding output voltage is 4.92 V.

A Novel Self-Adaptive Rectifier with High Efficiency and Wide Input Power Range

A novel 2.45 GHz self-adaptive rectifier with high efficiency and a wide input power range is proposed in this paper. It consists of a high-power sub-rectifier branch, a low-power sub-rectifier branch, an impedance transform and isolation network (ITIN), and a feedback network. Impedance matching is realized by ITIN for both branches. The proposed design is able to switch between these two branches by the feedback network according to its output voltage level. The rectifier has been simulated, fabricated, and tested. The measured power conversion efficiency (PCE) exceeds 50% over the input power range from 5 to 29 dBm, with a total dynamic range of 24 dB. The input range when PCE exceeds 60% is from 10 dBm to 28 dBm. The maximum efficiency is 75.2% at 26 dBm input power.

A Fully Integrated 0–200-MHz System BW Wireless Direct Sampling Receiver in 14-nm FinFET

This paper presents a fully-integrated wireless direct sampling receiver that covers from DC to 200MHz system bandwidth implemented with a single-channel SAR ADC in 14nm FinFET. To demonstrate the proposed architecture, frequency modulation (FM) among the applicable standard frequency bands is adopted as a prototype. The measured demodulated SNR is 73.9dB with -47dBm input power at 108MHz and the sensitivity level is -106dBm. The proposed direct sampling receiver shows a robust performance over a 30dB demodulated SNR even in the presence of the interference such as a strong adjacent channel and an in-band spur. Furthermore, the FM channel scan time is drastically reduced since the proposed receiver simultaneously samples all channels without adjusting analog building blocks.

Minimizing FWM Impact in DWDM ROF DP-DQPSK System for Optical

The demonstration of a higher data rate transmission system was a major aspect to be considered by researchers in recent years. The most relevant aspect to be studied and analyzed is the need for a reliable system to handle nonlinear impairments and reduce them. Therefore, this paper examines the influence of Four-Wave Mixing (FWM) impairment on the proposed high data rate Dual polarization–Differential Quadrature phase shift keying (DP-DQPSK) system using the Optisystem software. In the beginning, the impact of varied input power on the proposed system’s performance was evaluated in terms of QF and BER metrics. More power is used to improve system performance. However, increasing power would raise the FWM effects. Accordingly, a −10 dBm input power and the proposed system are used to reduce the impact of FWM. Additionally, a hybrid amplification method is proposed to enhance system performance by utilizing the major amplification methods of erbium-doped fiber amplifier (EDFA): semiconductor optical amplifier (SOA) and Radio optical amplifier (ROA). The evaluation demonstrates that the OA-EDFA outperformed the other two key amplification techniques of (EDFA-SOA) and (EDFA-ROA) in improving Quality factor (QF) and Bit error rate (BER) system results for all distances up to 720 km. Consequently, the method contributes to minimizing the impact of FWM. In the future, other forms of nonlinearity will be investigated and studied to quantify their impact on the proposed system.

High-Powered RF SOI Switch With Fast Switching Time for TDD Mobile Applications

This paper presents a fast switching and high-powered single-pole double-throw (SPDT) switch for RF switch circuits, such as TRx antenna switches and frequency band (or operation mode) selection switches in mobile handset applications. For fast switching time and performances of the RF switch, we proposed a novel method that can “selectively” control the impedance of a gate biasing circuit (“high” or “low” impedance). The proposed SPDT switch use the low impedance of the gate biasing circuit for fast switching time and use the high impedance of the gate biasing circuit to avoid the degradation of the insertion loss and harmonics. The proposed SPDT switch has no additional bias and no large payment for size consumption. According to measurement results, the turn-on switching time of the proposed SPDT switch was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.35~\mu \text{s}$ </tex-math></inline-formula> (at 2 GHz). The insertion loss, isolation, and return loss at 2 GHz were 0.16 dB, 47.1 dB, and 24 dB respectively. 2nd and 3rd harmonic levels at 25 dBm input power at 2 GHz were −88.7 dBm and −78.9 dBm, respectively. Power handling capability was 39.5 dBm of input power at 2 GHz. The designed SPDT switch was implemented in a 0.13- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> partially depleted silicon-on-insulator (PD-SOI) process.

Dispersion compensation analysis of 5.12 Tbps CSRZ based long-haul DWDM system

Abstract For this research article, we have completed the comparative performance analysis of 128 × 40 Gbps DWDM long-haul system for the ultra-transmission capacity of 5.12 Tbps using CSRZ modulation format under the impact of Kerr’s nonlinearities with symmetrical, post and pre dispersion compensation techniques. The BER, Q-factor values and eye-diagrams are considered as performance metrics for the different power levels ranging from −4 to 8 dBm and various transmission distances with the increment of 2400 km. We have used Gaussian filters (GFs) before multiplexing and after de-multiplexing for ensuring channel separation to evade the inter-symbol interference and cross-talk. The graphical performance analysis of the proposed system has also been made with the above mentioned compensation techniques at 4, 6 and 8 dBm input powers using DCF at 50 GHz frequency spacing for the optimization of the used format. It is observed that overall, symmetrical compensation gave better-quality performance at all the power levels in comparison to pre and post schemes. Due to narrow optical spectrum of CSRZ format, the proposed system has shown consistency, resilience and toughness against the bottlenecks appeared as dispersion and nonlinearities. It has supported the transmission distance of 19,200 km at 6 dBm optimum power for symmetrical compensation with BER of 8.65E-13 against Q-factor value of 7.00 as compared to pre compensation for 14,400 km at BER of 2.28E-13 with Q-factor of 7.18 whereas post compensation technique have shown a transmission distance of 16,800 km at 8 dBm optimum launched power with BER of 1.63E-12 and Q-factor value of 6.92.

A New Compact Triple-Band Triangular Patch Antenna for RF Energy Harvesting Applications in IoT Devices.

This work proposes a new compact triple-band triangular patch antenna for RF energy harvesting applications in IoT devices. It is realized on Teflon glass substrate with a thickness of 0.67 mm and a relative permittivity of 2.1. Four versions of this antenna have been designed and realized with inclinations of 0°, 30°, 60° and 90° to study the impact of the tilting on their characteristics (S11 parameter, radiation pattern, gain) and to explore the possibilities of their implementation in the architectures of electronic equipment according to the available space. The antenna is also realized on waterproof paper with a thickness of 0.1 mm and a relative permittivity of 1.4 for biomedical domain. All the antennas (vertical antenna, tilted antennas and antenna realized on waterproof paper) have a size of 39 × 9 mm2 and cover the 2.45 GHz and 5.2 GHz Wi-Fi bands and the 8.2 GHz band. A good agreement is obtained between measured and simulated results. Radiation patterns show that all the antennas are omnidirectional for 2.45 GHz and pseudo-omnidirectional for 5.2 GHz and 8.2 GHz with maximum measured gains of 2.6 dBi, 4.55 dBi and 6 dBi, respectively. The maximum measured radiation efficiencies for the three antenna configurations are, respectively, of 75%, 70% and 72%. The Specific Absorption Rate (SAR) for the antenna bound on the human body is of 1.1 W/kg, 0.71 W/kg and 0.45 W/kg, respectively, for the three frequencies 2.45 GHz, 5.2 GHz and 8.2 GHz. All these antennas are then applied to realize RF energy harvesting systems. These systems are designed, realized and tested for the frequency 2.45 GHz, −20 dBm input power and 2 kΩ resistance load. The maximum measured output DC power is of 7.68 µW with a maximum RF-to-DC conversion efficiency of 77%.

AlScN-Based SAW Magnetic Field Sensor for Isolated Closed-Loop Hysteretic Current Control of Switched-Mode Power Converters

This letter uses a surface acoustic wave magnetic field sensor for measurement and closed-loop current control of the inductor current in a GaN-based dc-dc power converter. The sensor is based on aluminium scandium nitride thin films with relatively high Sc concentration of 32% and fabricated on low-cost 8-in silicon substrate, with a magnetostrictive FeCoSiB film on top of a SAW delay line. The device has dc and bidirectional current measurement capability (derived from the magnetic flux density around a current trace) and is operated electrically isolated above the current trace. With permanent magnets as magnetic bias, the setup has a usable bidirectional current range of ±5 A. A phase detector IC measures the phase shift between the 296 MHz, 19 dBm input, and 35 dB attenuated output signal of the delay line sensor. The active sensor area has a distance of 2.5 mm from the current trace. In a 1.2 mT bias, the sensor is operated with a sensitivity of 18.28°/mT and bipolar current range of up to ±5 A. The sensor signal is enhanced by an analog filter to compensate the over 1 µs delay from the delay line and readout circuit. Finally, the sensor is used as the input of an analog hysteretic current control loop. The closed-loop current control operation is demonstrated using a 48 V GaN-based half-bridge dc-dc converter with 16 kHz triangular inductor current.

A novel class-E class-D doherty power amplifier based on past matching network with linearity region extension and flat output power

In this paper, a Doherty power amplifier (DPA) is proposed consisting of class-E as the main branch and class-D as the auxiliary power amplifier (PA). Past matching network is applied in the proposed DPA to control the output impedance and reduce its deviation from matching point, which provides improved bandwidth characteristic. The use of λ/4 lines for inductor modeling, employing power divider and input/output matching networks based on micro-strip stubs result in size reduction of proposed DPA, better isolation of the ports and lower return loss. The proposed Doherty structure is based on class-E in main branch and class-D in auxiliary branch, which provides high efficiency, and high output power in 2.7–3.5 GHz frequency band. The proposed DPA has drain efficiency of 65.4% and the gain of 18.6 dB in P-1dB point (27 dBm input power) where in this point, the output power is 45.87 dBm. In the saturation region, the output power of 48.6 dBm and drain efficiency of 93.7% can be obtained in the proposed DPA as shown in simulation results.

High‐efficiency broadband rectifier with compact size for wireless power transfer

AbstractIn this letter, an efficient broadband microwave rectifier with compact size for wireless power transfer is presented. It is proven that the proposed voltage doubler is easier to be matched than the series diode rectifier to achieve a wide bandwidth. In our analysis, the voltage doubler itself is already matched without the input matching network at the lower frequency band. For higher frequency band matching, a short section of microstrip line is connected to the input port of the voltage doubler. Thus, the proposed rectifier can operate over a broad bandwidth. To verify the design concept, a rectifier is fabricated, and the measurement results demonstrate that the power conversion efficiency is greater than 50% from 0.1 to 4.3 GHz at an 18 dBm input power level, and is higher than 70% within a wide bandwidth of 76.9%. In addition, when the input power is 18 dBm, the peak efficiency is 76.36% at 1.4 GHz. The results show that the proposed rectifier has the merits of compact size, broad bandwidth, and high efficiency.

The gain and noise figure comparison of single‐pass, double‐pass, and dual‐stage triple‐pass thulium‐doped fiber amplifiers in S‐band with thulium‐doped fiber optimization

AbstractThis study presents a comparison of three different S‐band thulium‐doped fiber amplifiers (TDFA) designs. The gain performances of the amplifiers are analyzed based on each scheme, separately. With −20 dBm input power, to provide ground‐state and excited‐state absorptions, the 1050 nm pump is used in all designs. The thulium‐doped fiber (TDF) lengths are optimized for maximum gain by using the single parameter single result optimization of Optisystem 18.0 software. A reflector is integrated into the double‐pass and dual‐stage triple‐pass TDFA to allow double propagation. Compared to double‐pass TDFA, in dual‐stage triple‐pass TDFA design, gain values increased without changing the stable bandwidth. 42.77 dB gain is demonstrated for two optimized TDF lengths; L1: 5 m and L2: 4.8 m, while noise figure values are higher than the other schemes. This comparison is important to show that the dual‐stage triple‐pass TDFA design could be suitable for obtaining higher gain in wider stable bandwidth in the fiber optic communication systems.

Compact and Efficient Broadband Rectifier Using T-type Matching Network

In this letter, a multioctave voltage doubler rectifier using a T-type matching network is demonstrated. The voltage doubler topology is used to flatten the load impedance, which makes it easier to achieve broadband impedance matching. The T-type matching network is used for the broadband input impedance matching. The design procedure of the proposed broadband rectifier is provided and discussed. For validation, a rectifier prototype is fabricated, and the performance is evaluated. The measured results exhibit power conversion efficiency (PCE) of more than 50% over a frequency band of 0.2–3.2 GHz at 15 dBm input power and 70% from 1 to 2.7 GHz. Moreover, the peak PCE is 78.2% at 1.9 GHz when the input power is 18 dBm.

A Compact Ultra-Broadband RF Rectifier Using Dickson Charge Pump

In this letter, an ultra-broadband rectifier is proposed and tested to get more RF energy from ambient. The rectifier using the Dickson charge pump increases the bandwidth and improves the dc voltage of the output load. The upper branch uses an inductor in series to counteract the capacitance of the imaginary parts of the diode and at the same time acts as a booster circuit to increase the output voltage. A shunt open-circuit stub acts as part of the matching network, tuning the imaginary part of the input impedance of the high frequency to realize the impedance matching of the ultra-broadband rectifier. The manufactured rectifier is measured and the result shows a fractional bandwidth of 145.5% (0.6-3.8 GHz) with an RF-to-dc power conversion efficiency (PCE) exceeding 40% at 8 dBm input power. And the measured efficiency remains over 50% across the frequency range from 1.6 to 3.4 GHz (including GSM1800, GSM2100, and WiFi). In addition, the rectifier made a maximum conversion efficiency of 66.6%.

A Multifunctional Battery-Free Bluetooth Low Energy Wireless Sensor Node Remotely Powered by Electromagnetic Wireless Power Transfer in Far-Field.

This paper presents a multifunctional battery-free wireless sensing node (SN) designed to monitor physical parameters (e.g., temperature, humidity and resistivity) of reinforced concrete. The SN, which is intended to be embedded into a concrete cavity, is autonomous and can be wirelessly powered thanks to the wireless power transmission technique. Once enough energy is stored in a capacitor, the active components (sensor and transceiver) are supplied with the harvested power. The data from the sensor are then wirelessly transmitted via the Bluetooth Low Energy (BLE) technology in broadcasting mode to a device configured as an observer. The feature of energy harvesting (EH) is achieved thanks to an RF-to-DC converter (a rectifier) optimized for a low power input level. It is based on a voltage doubler topology with SMS7630-005LF Schottky diode optimized at −15 dBm input power and a load of 10 kΩ. The harvested DC power is then managed and boosted by a power management unit (PMU). The proposed system has the advantage of presenting two different power management units (PMUs) and two rectifiers working in different European Industrial, Scientific and Medical (ISM) frequency bands (868 MHz and 2.45 GHz) depending on the available power density. The PMU interfaces a storage capacitor to store the harvested power and then power the active components of the sensing node. The low power digital sensor HD2080 is selected to provide accurate humidity and temperature measurements. Resistivity measurement (not reported in this paper) can also be achieved through a current injection on the concrete probes. For wireless communications, the QN9080 system-on-chip (SoC) was chosen as a BLE transceiver thanks to its attractive features: a small package size and extremely low power consumption. For low power consumption, the SN is configured in broadcasting mode. The measured power consumption of the SN in a deep-sleep mode is 946 µJ for four advertising events (spaced at 250 ms maximum) after the functioning of sensors. It also includes voltage offset cancelling functionality for resistivity measurement. Far-field measurement operated in an anechoic chamber with the most efficient PMU (AEM30940) gives a first charging time of 48 s (with an empty capacitor) and recharge duration of 27 s for a complete measurement and data transmission cycle.

A broad band energy harvesting rectenna based on metamaterial complementary split ring resonator broadband antenna and BALUN rectifier

In this paper, we present a new design of a broadband energy harvesting rectenna. The rectenna consists of a compact bidirectional complementary split ring resonator broadband antenna and a broadband Balanced to unbalanced rectifier. The antenna design offers a 60% size reduction comparing to the conventional designs. The realized rectenna operates at a large bandwidth that includes four main harvestable ambient frequency bands (GSM-1.8 GHz, UMTS-2.1 GHz, WiFi-2.45 GHz and 4G-2.6 GHz GSM). The prototypes have been printed on 1.58 mm thickness FR4 substrate with a permittivity of 4.3. The design shows a higher efficiency compatibility at the lower power levels where it has reached 72% at −6 dBm input power.

Design and implementation of static 2:1 frequency divider based on GaAs pHEMT

AbstractThis study presents a low phase noise static 2:1 frequency divider in a 0.15 µm gallium arsenide pseudomorphic high electron mobility transisitor process. The proposed divider is based on an improved source coupled logic structure. The maximum bandwidth utilization of the frequency divider is improved up to 100% through theoretical analysis. This frequency divider with low phase noise achieves an operating frequency of direct current ~4.8 GHz for 0 dBm input, and the phase noise is −131.06 dBc/Hz@10 MHz. The chip area is 0.624 × 0.923 mm.

All-Textile On-Body Antenna for Military Applications

An all-textile cavity-backed substrate integrated waveguide (SIW) antenna is proposed for military applications. The antenna matches standard military badge size. The aircraft-shape badge antenna that operates in X-band is designed for air force. SIW cavity and meandered slots that form the body and wing of the figure provide resonance at 8 GHz with 26&#x0025; bandwidth. Symmetrical boresight patterns with very low sidelobes are observed. The measured gain and efficiency of the structure are 5.2 dBi and 79.2&#x0025; at 8 GHz, respectively. This efficiency value is the highest among other SIW cavity textile-antennas. The antenna is investigated on conformal surfaces, as well. Bending of the antenna to follow body movements does not deteriorate performance of the textile antenna sensor. The peak specific absorption rate value over 10 g of tissue was 0.53 and 0.69 W&#x002F;kg for 30 dBm input power for female and male breasts, which makes it suitable as an on-body antenna. The badge antenna is fabricated with standard textile fabrication techniques and its simulation performance is confirmed successfully by measurements. Usage of standard off-the-shelf parts for the assembly and fabrication with standard textile fabrication techniques enables simple and cost-effective mass production of the proposed badge antenna.

A triple band rectenna for RF energy harvesting in smart city applications

ABSTRACT Radio Frequency Energy Harvesting is found to be the best alternative to conventional batteries for providing endless power to the sensor networks connected to perform various applications in the smart city. The electromagnetic energy density in the ambient environment is very low and not uniform, which demands a high gain multi-band rectenna system operating at mostly available energy bands and a suitable rectifier circuit that offers large PCE performance. This paper introduces a triple-band monopole rectenna with enhanced performance for smart city applications. A defective ground structure (DGS) has been investigated for a significant increase in gain with an increasing number of resonant frequencies. The proposed antenna operates over a band of frequencies that lies within 1.25–3 GHz, which covers 1.8/2.1/2.45 GHz frequencies. The antenna offers the gain values of 4.16/6.54/10.2 dB at 1.8/2.1/2.45 GHz frequencies, respectively. A single diode series-connected rectifier has been opted to efficiently operate over a wide range of input power levels from −10 dBm to 5 dBm and offers a minimum conversion efficiency of 60% within the operating bands at 0 dBm input power. The rectenna system is experimentally measured and the measured output voltage at 2.45 GHz frequency is 1.123 V.

Loop-gap microwave resonator for millimeter-scale diamond quantum sensor

The diamond quantum sensors based on NV (Nitrogen-Vacancy) center is one of the promising candidates for magnetoencephalography, which requires sub-pT/√Hz magnetic field sensitivity. To achieve high sensitivity, it is necessary to excite millimeter volume scale in diamond crystal by light and microwaves, and to collect fluorescence efficiently emitted from NV centers in the volume. We proposed and fabricated a printed circuit board-based loop-gap microwave resonator to improve the spatial uniformity of the microwave field to the millimeter volume scale. Moreover, our resonator can incorporate features such as efficient optical excitation and collection, and heat dissipation. Using this resonator, we demonstrated that the NV ensemble, formed by CVD process, were driven within an area of 5 mm square. The average strength of the microwave magnetic field was 0.53 G at 46 dBm input power, which is sufficient to drive the NV centers for our sensor. The uniformity of the microwave field strength was within 0.27G of the peak-to-peak amplitude for 1 mm3 volume. Differential input of microwaves into a loop-gap resonator with two gaps improves the peak-to-peak amplitude for 1 mm3 to 0.093 G in the simulation.

Semi-Annular-Ring slots loading for broadband circularly polarized DR-Rectenna for RF energy harvesting in smart city environment

This article describes a circularly polarized (CP) broadband rectenna enabling sensing nodes connected in the smart cities to harvest radio frequency (RF) energy from the surrounding atmosphere. The proposed antenna efficiently operates at the 5.8 GHz Wi-Fi band (5.725–5.875 GHz) and the Wi-Fi 6E band (5.925–7.125). The antenna is a semi-cylindrical dielectric resonator antenna (S-CDRA) energized by a microstrip feed. Semi-annular slots are introduced around a Bow-tie slot from the ground plane side, enhancing the bandwidth, gain, and CP characteristics. The antenna provides an impedance bandwidth (BW) of 2.89 GHz (5.45–8.34 GHz) and offers CP characteristics with an axial ratio (AR) bandwidth of 680 MHz (5.67–6.35 GHz). The antenna maintains a minimum gain of 4.8 dBic. A series-pair configuration is proposed for an extended operating range and better conversion efficiency. The maximum simulated and measured conversion efficiencies are 66.6% and 65.2% at 11 dBm input power, respectively.