RF Front-end Circuits Research Articles

Modeling Method of Multiplexed Sampling Electrical Parameter Characteristics Based on AIOT Sensing Module

Abstract In order to further reduce the errors arising in synchronous sampling, this paper designs a multi-channel hybrid sampling electrical parametric feature modeling method based on an AIOT sensing module in the process of design. The AIOT sensing module is used to process the received RF signals using a transconductance amplifier to improve the digitization and reconfigurability of the RF front-end circuit. The signal is transformed and calculated using the Fast Fourier Transform to obtain electrical parameters such as the amplitude of each harmonic and the power factor. The results show that the variation amplitude of the window function of the design method in this paper is generally maintained between -1.5 and 1.5, the amplitude accuracy of the active power rate is within 3.17555%, and the relative error accuracy is within 0.000951%. It can be seen that the AIOT-based sensing module can significantly improve the calculation accuracy of electrical parameters and can be applied to the process of sampling digital measurements of other power signal characteristics.

Chip Design of an All-Digital Frequency Synthesizer with Reference Spur Reduction Technique for Radar Sensing

5.2-GHz all-digital frequency synthesizer implemented proposed reference spur reducing with the tsmc 0.18 µm CMOS technology is proposed. It can be used for radar equipped applications and radar-communication control. It provides one ration frequency ranged from 4.68 GHz to 5.36 GHz for the local oscillator in RF frontend circuits. Adopting a phase detector that only delivers phase error raw data when phase error is investigated and reduces the updating frequency for DCO handling code achieves a decreased reference spur. Since an all-digital phase-locked loop is designed, the prototype not only optimized the chip dimensions, but also precludes the influence of process shrinks and has the advantage of noise immunity. The elements of novelties of this article are low phase noise and low power consumption. With 1.8 V supply voltage and locking at 5.22 GHz, measured results find that the output signal power is −8.03 dBm, the phase noise is −110.74 dBc/Hz at 1 MHz offset frequency and the power dissipation is 16.2 mW, while the die dimensions are 0.901 × 0.935 mm2.

A Wideband Sub-㎓ Receiver Front-end Supporting High Sensitivity and Selectivity Mode

A low noise and highly linear wideband RF front-end circuit for sub-㎓ Internet of Things (IoT) applications is proposed. The proposed frontend is composed of a broadband single-ended LNA, a wideband differential LNA employing thermal noise cancellation technique, and an in-phase and quadrature (I/Q) linearized harmonic rejection mixer (HRM). Depending on the interference environment, the proposed front-end supports two operation modes having high sensitivity and selectivity performance by enabling or disabling the first building block of the single-ended LNA. At high sensitivity mode, the frontend shows a voltage gain (A<SUB>v</SUB>) of greater than 38 ㏈, a noise figure (NF) of less than 2.1 ㏈, an input-referred third-order intercept point (IIP3) of greater than -23 ㏈m, and an input-referred second-order intercept point (IIP2) of greater than +15 ㏈m in the sub-㎓ frequency band. Concerning for high selectivity mode, it achieves an Av of greater than 22.5 ㏈, a NF of less than 4.7 ㏈, an IIP3 of greater than – 6.8 ㏈m, and an IIP2 of greater than +50 ㏈m over the same operating frequency range.

A Low-Power High Gain and High Linearity CMOS RF Front-End Design Involving a Charge Injection Mixer for V2X Technology

In this paper, an RF front-end (RFFE) circuit consisting of a low noise amplifier (LNA) and a down-conversion mixer for vehicle-to-everything (V2X) applications in a 65-nm CMOS process is presented. V2X standard has a carrier frequency of 5.9[Formula: see text]GHz with 10 and 20[Formula: see text]MHz bandwidth options. The LNA topology of the RFFE is based on an inductively degenerated cascode common source differential approach. The mixer design uses a double-balanced topology with a charge injection method to enhance the linearity and noise figure performance. The RFFE design shows a single sideband integrated noise figure of 4.47[Formula: see text]dB with a total conversion gain of 28[Formula: see text]dB. The IIP3 is obtained as [Formula: see text]17[Formula: see text]dBm with charge injection in the mixer which is an improvement of 5[Formula: see text]dB as compared to no charge injection. The design consumes a total current of 10.24[Formula: see text]mA from a 1.2-V supply. This work is the first CMOS RFFE design implemented for V2X applications.

Mechanism and protection on the data link of UAV exposed to electromagnetic interference

To solve the problem that the data link of the unmanned aerial vehicle (UAV) is vulnerable to electromagnetic interference during the flight and cause the link interruption, we took a certain data link of UAV as our research object, and proposed an experimental method of injection effect based on front door coupling. On this basis, we developed the effect experiment for the data link of UAV. We derived the sensitivity threshold curve of the data link and determined the sensitivity threshold, analyzed the work principle of RF front end circuit of the data link and the signal transmission process of the receiver under the effect of electromagnetic interference, revealed the mechanism of combined frequency interference and out of band saturation interference on data link, and finally carried out the experimental verification. Based on the test results, we put forward the corresponding protective methods from the aspects of the circuits level and adaptive control respectively.

Digital Electronics as RFID Tags: Impedance Estimation and Propagation Characterization at 26.5 GHz and 300 GHz

This article presents a circuit impedance model and results of propagation characterization at 26.5 GHz and 300 GHz for a new type of RFID tag that is based on digital electronics. This RFID tag leverages the backscatter radio generated from switching of transistors inside digital circuits, which does not need antennas or RF front-end circuits thereby further reducing the device’s form factor. Moreover, the proposed RFID tag is compatible with a wide range of interrogating frequencies and can be implemented on existing electronics without additional cost. The proposed circuit impedance model explains the modulation mechanism of this new backscatter radio and provides an estimation of digital circuits’ impedance using SPICE model parameters. Based on the proposed circuit impedance model, we develop a modified modulation loss factor to estimate the modulation loss resulting from the switching activity of the digital electronics. Furthermore, propagation characterization is conducted at 26.5 GHz and 300 GHz, where the shadowing gain for the carrier power and the backscattered power is characterized as 3.93 dB and 0.96 dB at 26.5 GHz, and 1.01 dB and 0.52 dB at 300 GHz, respectively, showing that the backscatter channel can provide a more reliable link that is resistant to the constructive and destructive interference from the multipaths as compared to the carrier channel.

Phase noise estimation method for RF front-end circuit of GNSS receiver

Phase noise estimation method for RF front-end circuit of GNSS receiver

A fully CMOS RF down-converter with 81.88 dB SFDR for IEEE 802.15.4 based wireless systems

In this paper, the challenges of dense integration, low power, low-cost, low-noise and high spurious free dynamic range (SFDR) required by the RF front-end (RFE) circuits for low-rate wireless personal area networks are addressed. The proposed RF down-converter circuit utilizes a low-noise transconductance amplifier stage to improve the noise performance of the highly noisy switching stage of the down-converter. The nonlinearity of the low-noise stage is compensated by employing post-distortion based harmonic cancellation for dynamic range improvement of the RF front-end circuit. The proposed RFE is designed and realised in UMC 180 nm CMOS process technology. The post-layout characterization of the circuit shows an third-order intercept point with reference to the input (IIP3) of 11.83 dBm, double-sideband noise figure of 5.9 dB, conversion gain of 17.87 dB and offers a SFDR of 81.88 dB while consuming 5 mA current from 1.8 V. The proposed circuit consumes an area of 0.1 mm2. The proposed RF down-converter boasts a 17 dB improvement in SFDR over the recently proposed RFE in the literature. The proposed RFE is also correlated with the other existing state-of-art RFE circuits recorded in the literature for Zigbee applications.

ADS optimization design of GPS RF front-end circuit with auto gain control

A GPS RF front-end receiving circuit is designed in accordance with the superheterodyne. The stage of the mixer is three and the signal of hybrid frequency is optimized through multiple filters to suppress the image signal. The ADS is used to establish the simulation platform for the RF front-end receiving circuit based on the L1 wave band. The pre-LNA is used to reduce system noise while the auto gain control element is used to achieve a large dynamic range of the RF receiver front-end. The parameters of the RF front-end including sensitivity, noise figure, IP3 and other indicators were simulated by the software simulation tools. The results indicate that this circuit could successfully implement the down-conversion and reception of radio frequency signal and meet the requirements of the design.

Design of Micro-strip Symmetrical Dual-band Filter Based on Wireless Sensor Network Nodes

The micro-strip antenna filter design of wireless sensor network nodes is usually used to improve the out-of-band suppression and frequency selectivity by increasing the order of the filters, but the filters are usually single band, not only the size is large, but also the in-band characteristics of the filters are not ideal. This paper proposes a method to design a micro-strip symmetric dual-band filter in wireless sensor network nodes. Firstly, the coupling matrix of single-passband filter is obtained by using the synthesis method of generalized Chebyshev filter function. Then, the coupling matrix of the dual-passband filter is generated according to the reflection zeros and the transmission zeros. Finally, the S parameters response curve is drawn by mapping the normalized frequency domain of the dual-passband to the actual frequency domain. According to the data analysis and experimental results, the method is feasible and effective to design a micro-strip symmetrical dual-band filter. It can not only provide a more guiding design method for the joint design of antenna and RF front-end circuit, but also realize the spread of single-passband filter to multi-frequency for a wireless sensor network node antenna.

MmWave communications for 5G: implementation challenges and advances

The requirement of the fifth generation (5G) wireless communication for high throughput motivates the wireless industry to use the mmWave (millimeter wave) communications for its wide bandwidth advantage. To compensate the heavy path loss and increase the communications capacity, phased array beamforming and massive multiple-input multiple-output (MIMO) techniques are employed at both the user equipment (UE) and base stations (BS). Considering the commercial requirements, 5G mmWave large array systems should be implemented in an energy- and cost-efficient way with a small form factor. To address above issues and realize a reliable communications link, taking into account the particular characteristics of 5G mmWave systems, this paper firstly examines the design challenges and trade-offs in system implementations, then some of the design strategies are summarized. At last, recent advance in RF front-end circuits and receiver sub-systems is then highlighted.

A Compact V-Band Planar Gap-Coupled $4\times 1$ Antenna Array: Improved Design and Analysis

In this paper, a broadband 60-GHz millimeter-wave $4\times 1$ microstrip patch antenna array using the gap-coupled technique is presented and analyzed. In order to meet the challenging requirement of reduced size related to this kind of technique, and facilitate the integration with other integrated passive or active devices, the proposed antenna array has been designed on a thin ceramic substrate ( $\varepsilon _{r} = 9.9 $ and $h = 127~\mu \text{m}$ ), using an miniature hybrid microwave integrated circuits (MHMIC) fabrication process. The proposed structure is based on a modified shape of a gap-coupled patch element with curved radiating edges. For further analysis, the performances of the latter in terms of impedance bandwidth, gain, and radiation efficiency were investigated and compared with a conventional structure of a rectangular gap-coupled patch antenna. The obtained results clearly show that the proposed gap-coupled array structure provides an improved bandwidth (7%) and an enhanced gain (10.7 dB), while maintaining a reduced size (5.2 mm $\times9.5$ mm). All these benefits make it an attractive candidate for the future integrated millimeter-wave RF front-end circuits; it can, however, be connected directly to various MHMIC passive circuits, or active devices through using the wire bonding technology, on a standard thin-film alumina substrate.

Design of Smart Switched-beam RFID Reader Based on DSP

The reader system of the UHF RFID is based on AS3992. And its read-distance is about 20m. The hardware’s design and software’s programming are introduced in detail. The design of the hardware is composed of the MCU (TMS320C5509A) circuit, the RF front-end circuit, the power divider and the phase shifter circuit. The programming of the software contains the ISO/IEC18000-6C protocol, the smart switched-beam algorithm, the power control algorithm, and the communication between the microcontroller and the PC through UART. The experimental results show that the reader has many features such as fast recognition speed, long read-distance, large coverage, anti-interference. The system can operate stably, so it has good application prospect.

A stacked sierpinski gasket fractal antenna with a defected ground structure for UWB/WLAN/RADIO astronomy/STM Link applications

ABSTRACTAn aperture coupled stacked Sierpinski gasket fractal antenna with a defected ground structure is proposed in the current article for ultra wide band (UWB) and wireless local area network (WLAN) applications. The radiating structure is formed of two Sierpinski gasket fractal patch antenna layers on two layers of FR4 substrate stacked one over the other. This stacked structure is fed by a third (bottom) layer also of FR4 substrate, with ground layer at its top and the feed line with a stub, at the bottom. The top ground layer has a ‘†’ shaped slot cut in it to provide a wideband behavior to the antenna, and the feed line is designed with a stub to provide circular polarization to the EM fields radiated by the proposed antenna. The antenna is designed using CST Microwave Studio version 2010 assuming perfect boundary conditions. The proposed antenna shows a dual band wideband behavior with an impedance bandwidth of 630 MHz (4.75–5.38 GHz) and 400 MHz (6.8–7.2 GHz) with a gain of 5.85 dB and 9.5 dB at the center frequencies of the two bands, respectively. The antenna is capable of covering two UWB bands from (4.75–5.28) GHz and (6.8–7.2) GHz, a radio astronomy band from (5.01–5.03) GHz and IEEE 802.11a band from (5.15–5.35) GHz. The prototype of the proposed antenna is tested using a VNA and an anechoic chamber to validate against the simulated results. The proposed antenna has volumetric dimensions of 6 × 6 × 0.483 cm3 which makes it a suitable choice for RF front end circuits. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2786–2792, 2015

A 85-mW Multistandard Multiband CMOS Mobile TV Tuner for DVB-H/T, T-DMB, and ISDB-T Applications with FM Reception

A fully integrated multistandard multiband CMOS mobile TV tuner with small silicon area and low power consumption is proposed for receiving multiple mobile digital TV signals and FM signal. In order to reduce the silicon area of the multistandard multiband receiver, other RF front-end circuits except LNAs are shared and a local oscillator (LO) signal generation architecture with a single VCO for a frequency synthesizer is proposed. To reduce the low frequency noise and the power consumption, a vertical NPN BJT is used in an analog baseband circuits. The RF tuner IC is implemented in a 0.18-mm CMOS technology. The RF tuner IC satisfies all specifications for DVB-H/T, T-DMB, and ISDB-T with a sufficient margin and a successful demonstration has been carried out for DVB-H/T, T- DMB, and ISDB-T with a digital demodulator.

Adaptive TX Leakage Canceler for the UHF RFID Reader Front End Using a Direct Leaky Coupling Method

This paper presents a new adaptive leakage canceler based on a direct leaky coupling method for an RF front-end circuit of an ultrahigh-frequency radio-frequency identication (UHF RFID) reader. For better receiver sensitivity, the leakage signal from a transmitter (TX) to a receiver (RX) should be suppressed. Compared with conventional methods, the proposed TX leakage canceler has a much simpler circuit configuration due to the direct leaky coupling circuit (LCC) and the phase shifter on the RX path. The LCC includes a variable resistor, a variable capacitor, and an inductor, which allow us to control the magnitude and the phase of the coupled TX signal. The phase shifter that is located on the RX path even before the low-noise amplifier controls the phase of the TX leakage signal. For the worldwide RFID bands that spans from 840 to 960 MHz, the canceler must be adaptively controlled by using a microcontroller and control circuits. For the experimental verification, an RF front-end circuit with the proposed adaptive TX leakage canceler was designed and implemented for the UHF RFID reader. The implemented RF front-end block occupies only 54 ×54 mm2, except for the control block. From 840 to 960 MHz, the adaptively controlled RF front-end circuit exhibited significant cancelation characteristics for the TX-RX leakage signals. This results in more than twice longer reading distances for the commercial RFID tags compared with the cases without the adaptive canceler.

Performance analysis of a low power low noise tunable band pass filter for multiband RF front end

This paper presents a low power tunable active inductor and RF band pass filter suitable for multiband RF front end circuits. The active inductor circuit uses the PMOS cascode structure as the negative transconductor of a gyrator to reduce the noise voltage. Also, this structure provides possible negative resistance to reduce the inductor loss with wide inductive bandwidth and high resonance frequency. The RF band pass filter is realized using the proposed active inductor with suitable input and output buffer stages. The tuning of the center frequency for multiband operation is achieved through the controllable current source. The designed active inductor and RF band pass filter are simulated in 180 nm and 45 nm CMOS process using the Synopsys HSPICE simulation tool and their performances are compared. The parameters, such as resonance frequency, tuning capability, noise and power dissipation, are analyzed for these CMOS technologies and discussed. The design of a third order band pass filter using an active inductor is also presented.

RF MEMS for Reconfigurable RF Front-End: Research in Australia

This paper reviews some ground breaking development of RF MEMS technology in Australia at the UNSW, over the past decade. It presents some unique and novel designs using RF MEMS switches to achieve reconfigurable RF front-end circuits. These designs include multiport RF MEMS switches, switch matrices, reconfigurable filters and antennas. The resulting devices achieved RF performance that is unmatched by any existing RF andmicrowave technologies.

Single-Layer Differential CPW-Fed Notch-Band Tapered-Slot UWB Antenna

A single-layer differential coplanar waveguide (CPW)-fed notch-band tapered-slot ultrawideband (UWB) antenna is proposed in this letter. In order to achieve the sharp and controllable notch-band characteristic, one pair of half-wavelength stubs and slits are introduced inside the tapered slot and in the circular patches, respectively. Compared to a single-ended CPW-fed UWB antenna, due to adopting the differential feeding structure, the proposed antenna has lower cross polarization. Since all of the structures are printed on the same layer of the substrate, it can be fabricated easily and very suitable to be integrated with RF front-end circuits. The measured -10-dB impedance bandwidth is 126% (from 2.78 to 12.3 GHz), along with a sharp notch band from 5.2 to 6.0 GHz. Good agreement is achieved between the measured results and simulated results.

Performance Analysis of Tunable Band Pass Filter and VCO for Multiband RF Front End

This paper presents a design and performance analysis of tunable RF front end circuits such as RF band pass filter and VCO for multiband applications. The tunable element is an active inductor, built by MOS transistors. It is attractive due to its tunable and larger inductance values. The RF band pass filter is realized using active inductor with suitable input and output buffer stages. The tuning of center frequency for multiband operation is achieved through the controllable current source of the active inductor. The tunable range of the band pass filter varies from 3.9 GHz to 12.3 GHz. The simulation results of band pass filter have minimum noise figure of 23 dB and has less power dissipation of 2.83mW. The simulated IIP3 is -9.6dBm for 1st and 3rd order frequency of 7.94 GHz and 7.93 GHz respectively. The VCO designed using active inductor has the tuning range of 0.384 GHz to 1.620 GHz with the phase noise of -139dBc/Hz at the offset of 1MHz. It consumes less power of 1.754mW with the figure of merit of 189dBc/Hz. The designed active inductor, RF band pass filter and VCO are simulated in 180nm CMOS process using Synopsys simulation tool.