Concurrent Dual-Band Research Articles

Optimization Analysis of Low-Noise Amplifier

This paper mainly analyzes the important component of a wireless receiver – low-noise amplifiers (LNA). Low-noise amplifiers can reduce the effect of noise on the received signal and amplify signals. For the better development of wireless communication technology, remote control, and other related fields, it is necessary to optimize the design of low-noise amplifiers, so that low-noise operational amplifiers can finally obtain high gain, low noise figure, and other advantages. This paper analyzes the optimization design of LNA in the field of Global Navigation Satellite Systems (GNSS). This paper analyzes a low-noise amplifier design with the operation of concurrent dual-band for GNSS receivers with a single channel. The optimized design of a low-noise amplifier in this field uses a low-cost 0.18µm CMOS tube and adds load capacitances and a feedforward path to reduce the noise figure (NF) of the system. Noise figures in 1.2 GHz and 1.57 GHz bands are reduced by about 0.9 dB. In addition, the high gain, high linearity, and other excellent properties are shown in 1.2 GHz and 1.57GHz. In the application of 5G/6G network technology, the optimized design of Gallium Arsenide (GaAs) PHEMT technology with a gate length of 0.3µmm and inductively degraded common source topology phase structure is adopted. From this optimization, the noise figure is optimized to 1.3-1.4, and the gain of the system is 20-22 dB. At the same time, good linearity is also shown. Then, the prospects of semiconductor materials such as Gallium Nitride (GaN) and Indium Phosphide (InP), which have the advantages of high electron mobility and low-cost design, in optimizing low noise operational amplifiers. To a certain extent, the in-depth study of the optimal design of LNA can improve the technical level of wireless communication, aerospace, and other fields.

Calibration Techniques for Concurrent Dual-Band Multiport Receivers

Calibration Techniques for Concurrent Dual-Band Multiport Receivers

A Pseudo-Differential LNA with Noise Improvement Techniques for Concurrent Multi-Band GNSS Applications

A low-noise amplifier (LNA) design with the operation of concurrent dual-band for Global Navigation Satellite System (GNSS) receivers with single channel is presented in this work. This LNA structure has an inductively degenerated cascode architecture and is pseudo-differential, operating at two frequencies simultaneously (1.2 GHz and 1.57 GHz). Two noise reduction/cancellation techniques, using load capacitor and feedforward path, respectively, are proposed resulting in an excellent improvement in the noise figure (NF). The input matching circuit uses both series and parallel resonant components to enable concurrency. The adopted pseudo-differential structure results in input balun elimination. Inductively degenerated cascode topology provides both input impedance and optimum noise impedance matching. The soundness of the proposed approach has been demonstrated in a 0.18-µm CMOS technology by TSMC. Simulation results show that at 1.2 GHz and 1.57 GHz the LNA achieves −13 dB and −11 dB of input matching, 24.6 dB and 24.7 dB of gain, 1.47 dB and 1.43 dB of NF, respectively. The input-referred 1-dB compression point (IP1dB) is around −16 dBm, while the input-referred third-order intercept point (IIP3) achieves −2.2 dBm at 1.2 GHz and −0.6 dBm at 1.57 GHz. The LNA draws about 13 mA from a 1.8-V supply voltage.

C/Ka Concurrent Dual-Band GaN MMIC Based on Shorted Quarter-Wavelength Line Topology

C/Ka Concurrent Dual-Band GaN MMIC Based on Shorted Quarter-Wavelength Line Topology

Compact Self-Oscillating Active Integrated Loop Antenna With Concurrent Dual-Band Operation

Compact Self-Oscillating Active Integrated Loop Antenna With Concurrent Dual-Band Operation

The Effect of IMD Drain Impedances in RF PA Concurrent Dual-Band Operation

This article develops a theory to explain the effect of controlling the impedance at the intermodulation distortion (IMD) frequencies, related to the first-order passband distortion terms (generated through <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(n+1)\cdot f_1-n\cdot f_2$</tex-math> </inline-formula> or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(n+1)\cdot f_2-n\cdot f_1$</tex-math> </inline-formula> ), for radio frequency (RF) power amplifiers (PAs) operating in the concurrent dual band. It is shown that, similar to harmonic terminations in the single-band operation, the IMD impedance of these terms can significantly impact efficiency and output power. Careful tuning of these IMD terminations shapes the envelope of the RF signal, akin to RF wave shaping. Through this shaping, it is theoretically possible to achieve the same efficiency in single and concurrent band operations, instead of the expected <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sfrac{\pi}{4}$</tex-math> </inline-formula> multiplicative drop. To demonstrate the practical importance of considering the impedance at these IMD frequencies, a dual-band RF PA is designed with a trimmed third-order IMD ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 \cdot f_2-f_1$</tex-math> </inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 \cdot f_1-f_2$</tex-math> </inline-formula> ) impedance. The power and efficiency performance of the PA in dual band exceeds the estimations drawn from the single-band operation characteristics and is in accordance with the developed theory.

A Novel Concurrent Dual Band Matching Network for Complex to Real Impedance Matching for RF Applications

A novel and simple technique to match Frequency Dependent Complex Loads (FDCLs) to real source impedance at any two arbitrary frequencies is presented. The proposed structure consists of stubs and two 50 Ohms series transmission lines, making it easy to fabricate. This arrangement allows concurrent operability. It has the versatility to transform all types of complex loads at any frequency ratio, which may not be possible with other conventional techniques. In this brief, the limitations of single section transmission line to transform FDCLs to two complex conjugate loads (CCLs) at two frequencies is thoroughly studied. In the proposed scheme, an L-section is used to match the complex load to source impedance at one frequency; and another section consisting of a transmission line and a combination of open-short stub is used to match the load at other frequency. Three prototype matching networks for frequency ratios 6.5, 2.3 and 1.583 are designed and implemented on ROGERS RO4003 substrate having dielectric constant of 3.38 and substrate height of 20 mils. The simulated and the measured results are in a good accordance.

Design of a dual-band microwave power amplifier for wireless communications

In this paper, we present a design of a concurrent dual-band power amplifier operating at 5.8 GHz and 9.4 GHz employing a MMIC technology for wireless communications. The active device used is a 0.25 µm AlGaN/GaN HEMT from WIN Semiconductor, Taiwan. The design goal is to achieve the high-efficiency while still retaining other important metrics including output power and power Gain at concurrent dual frequency bands. The performance of the designed amplifier is evaluated at both small and large signal levels through theoretical analyses and simulation using a Keysight ADS simulator. The developed dual-band amplifier delivered a 47% PAE with 30.5 dBm output power and 12.5 Gain at 5.8 GHz, and a 37% PAE with 30.2 dBm output power and 12.2 Gain at 9.4 GHz.

Design and Analysis of an Electrical Balance Duplexer With Independent and Concurrent Dual-Band TX-RX Isolation

An electrical balance duplexer (EBD) supports dual-band TX-RX isolation enabling frequency-division duplexing (FDD) operation at 5-7 GHz for Wi-Fi 6/6E. A programmable balance network in the EBD can balance the antenna impedance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Z_{\text {ANT}}$ </tex-math></inline-formula> ) in the TX channel and RX channel independently and simultaneously. An on-chip passive bandstop filter as a part of the balance network is implemented, achieving sub-2-dB passband insertion loss (IL) and >20-dB stopband rejection with 10% frequency spacing. This filter separates two impedance tuners in the balance network and enables the independent tunability at two bands. A comprehensive and rigorous analysis of general <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCR</i> two-ports shows the limit of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$s_{21}$ </tex-math></inline-formula> frequency selectivity when built with finite- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> elements. The analysis guides the filter design, which guarantees the maximum frequency selectivity. The analysis is then extended to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCR</i> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${N}$ </tex-math></inline-formula> -ports as the complete analysis. The EBD provides >40-dB isolation in an 80-MHz channel bandwidth in the TX band (5-6 GHz), for any <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Z_{\text {ANT}}(f_{\text {TX}})$ </tex-math></inline-formula> within VSWR = 2, and independently in the RX band (6-7 GHz) when <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q_{\text {ANT}}&lt; 4.3$ </tex-math></inline-formula> . The EBD is designed for ≤4-dB RX IL and ≤3.8-dB TX IL, and it supports +29-dBm TX output. The EBD is implemented in Towerjazz 65-nm RF silicon-on-insulator (SOI) CMOS technology and occupies an area of 2.3 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

An Analog Baseband Circuit for Wireless Local Area Networks Transceiver in 55 nm CMOS Technology

The design of the analog baseband circuit is based on 55 nm CMOS technology and is integrated in an IEEE 802.11ax concurrent dual band four antenna transceiver. A low-pass filter (LPF) of the receiver was multiplexed with an LPF-transmitter such that the last three stages of the fifth order LPF-receiver were used by the LPF-transmitter, and the first programmable gain amplifier (PGA) of the receiver was partially multiplexed with the PGA-transmitter such that the PGA-receiver and the PGA-transmitter shared the same operational amplifier and input resistance, thereby reducing the power consumption, noise, linearity, and area of intermediate frequency (IF) of the transmitter designed separately. The typical bandwidth of the IF-receiver is 10/20/40 MHz; that of the IF-transmitter is 12/24/50 MHz. The gain range of the IF-receiver and the IF-transmitter is 0.1–65.5 dB and −10.1 to 3.98 dB, respectively. Under the voltage of 1.5 V, the current of the IF-receiver is 3.86 mA. As for the IF-transmitter, the current is 1.78 mA when supply voltage is 1.5 V. The input referred noise (IRN) of the IF-receiver at 10 MHz bandwidth (BW) and 62 dB gain is 14.52 nV/√ Hz, while the IRN of the IF-transmitter at 10 MHz BW and −6 dB gain is 95.16 nV/√ Hz. The suppression ability of the DC offset cancellation circuit is 35.08/80.9/110.1/113 dB. The area of the analog baseband circuit is 0.17 mm2.

A Digital Predistortion for Concurrent Dual-Band Power Amplifier Linearization Based on Periodically Nonuniform Sampling Theory

In this article, we propose a novel technique of digital predistortion (DPD) for dual-band power amplifiers (PAs) based on the periodically nonuniform sampling (PNS) theory. In contrast to conventional dual-band DPD (2-D-DPD) models, the proposed periodically nonuniform sampled DPD (PNS-DPD) has only a single input, which can largely reduce the model complexity. We fold the two stimuli with aliasing and feed them to a simple single-band DPD model. The desired predistorted signals are reconstructed from aliased DPD output through the PNS theory. Compared with conventional multi-input models that include numerous intermodulation products of the input signals, the complexity of the proposed single-input PNS-DPD model is hugely decreased. The model coefficients of the proposed PNS-DPD can be easily extracted with conventional direct or indirect learning architecture. We experimentally evaluate the proposed DPD on a test bench and compare it with other DPD techniques in the literature. The implementation complexity can be reduced by over 30%, and the identification complexity is also largely reduced.

Concurrent Dual-Band Heterodyne Interferometric Receiver for Multistandard and Multifunction Wireless Systems

Radio frequency (RF), microwave, and millimeter-wave (mmW) multiport interferometric receivers present a competitive solution for the front-end reception of low-power multistandard and multifunction wireless applications. The systematic generation of rectified waves in a conventional direct-conversion interferometric receiver is highly related to temporal and power changes and the number of subsignals in the frequency band of interest. It can cause the receiver to saturate and, thus, requires auxiliary power-hungry tunable amplifiers and a data converter for compensation. This work presents a heterodyne detection in an RF/microwave interferometric receiver, the first of its kind, which separates the desired frequency signals from the rectified wave components with two output ports through a frequency offset. This architecture also makes use of the field-effect transistor (FET)-based power detectors to combine the received and reference signals, which reduces a theoretical multiport junction loss of 6 dB to 3 dB. In this way, the proposed receiver is set to support the development of an ultralow-power concurrent dual-band wireless system using a single wave-correlator circuit. A mathematical model of the proposed system is derived and subsequently prototyped using off-the-shelf components to evaluate its carrier-to-noise power ratio (CNR) and error vector magnitude (EVM) performances, which can be extended for integrated circuits (ICs) implementation, such as CMOS and III–V ICs. The power detectors only require a bias voltage at gate terminals with zero direct current (dc) power consumption for optimum voltage responsivity and CNR performances. The demodulation of various modulated digital signals, including QPSK, QAM-16, QAM-32, and QAM-64, has been successfully demonstrated in the 24- and 28-GHz mmW frequency bands at 4 MSps of the symbol rate with a maximum EVM of 11.43% root-mean-square (rms) free from any postprocessing linearization and calibration.

Compendious Concurrent Dual-Band Receiver Based on Multiport Interferometric Architecture

A distinct usage of the conventional multiport architecture is introduced in this work to explore the compendious scheme of a concurrent dual-band interferometric receiver. Dual RF signals at individual frequency channels are received simultaneously, and only a single low-power local oscillator (LO) source is deployed for frequency translation or conversion to the same intermediate frequency (IF) band. Although these signals are spectrally overlapped, they can be extracted with a simple and efficient algorithm with good channel-to-channel isolations. Compared to the conventional multiport configuration, the power detectors are replaced by analog-to-digital converters (ADCs) to process the signals in this proposed scheme. The underlying physics of the concurrent receiving operation is explained and derived analytically. Some experiments are also presented to investigate various performance indexes, including signal linearity, noise behavior, interchannel interference, and so forth. Lastly, multiple M-quadratic-amplitude modulation (QAM) signals are applied to evaluate the communication behavior of the proposed receiver architecture. Distortions due to frequency drift, channel imbalance, and in-phase and quadrature (IQ) imbalance are studied, and bit-error-rates (BER) are measured and compared with their theoretical counterparts. All obtained results confirm that the proposed interferometric receiver provides good communication performances.

A 3rd/5th Order Active RC Chebyshev Analog Baseband Low-Pass Filter With Reconfigurable Bandwidth and Gain

The design of 3rd/5th order active RC Chebyshev low-pass filter (LPF) with reconfigurable bandwidth and gain is based on 55 nm CMOS technology. The filter is integrated into draft IEEE 802.11ax concurrent dual band four antenna transceiver analog baseband circuit. Programmable capacitor bank of the filter is used to adjust bandwidth. The typical bandwidth of receiving filter is 10/20/40 MHz, and that of transmitting filter is 12/24/50 MHz. Adjust the gain ranging from -10 to 18 dB in passband by programmable resistor bank. The current consumption of typical bandwidth of receiving filter is 2.08 mA at a 1.5 V supply and has properties of 10 MHz bandwidth (BW), 36 dB gain, -62 dBm input signal, -39 dB third intermodulation distortion (IMD3), 17.1 nV/√Hz equivalent input noise (EIN). As for transmitting filter, the current consumption of typical bandwidth is 1.25 mA at a 1.5 V supply and has the properties of 10 MHz BW, -6 dB gain, 0 dBm input signal, -38 dB IMD3, 75 nV/√Hz EIN. Area of the whole filter is 0.08 mm2.

Low Phase Noise Concurrent Dual-Band (5/7 GHz) CMOS VCO Using Gate Feedback on Nonuniformly Wound Transformer

A novel low phase noise concurrent dualband complementary metal-oxide-semiconductor (CMOS) voltage-controlled oscillator (VCO) employing a gate-feedback enabled, nonuniform multiwinding transformer is proposed. The transformer consists of the wide-width looped main inductors and surrounding narrow-width looped feedback inductors, featuring a high degree of design freedom, owing to its controllable width, gap, and coupling coefficients. This novel topology enables both simultaneous and independent oscillation in two frequency bands using the main inductors with oscillation cores. In addition, the resonant tank's noise contribution can be reduced by boosting the loaded quality factor using gate-driving feedback inductors. The proposed VCO was fabricated in a 0.28-μm silicon on insulator (SOI) CMOS process. The measured results show concurrent oscillation from 4.6 to 5.6 GHz and 6.1 to 7.4 GHz with phase noise of -119.3 and -120.1 dBc/Hz at 1 MHz offset, corresponding to a figure-of-merit (FOM) of -184.4 and -185.1, whereas the FOM for low-band and high-band single-tone oscillation is -182.7 and -184.8 dBc/Hz, respectively. Finally, the FOM of the proposed VCO is compared with that of similar size concurrent dual-band VCO devices previously presented in literature.

Double Functionality Concurrent Dual-Band Self-Oscillating Mixer

A concurrent dual-band self-oscillating mixer (SOM), based on a ring-shaped stepped-impedance resonator, is proposed and analyzed in detail. Taking advantage of the ring even and odd resonances, the circuit can operate in concurrent dual quasi-periodic mode and injection-locked mode. In the second case, it behaves as a dual-band zero-intermediate-frequency (IF) mixer. Initially, an analytical study of the SOM behavior in the two modes is presented. Then a variety of accurate numerical methods are used for an in-depth investigation of the main aspects of its performance, including stability, conversion gain, linearity, and phase noise. The recently proposed contour-intersection technique and the outer-tier perturbation analysis are suitably adapted to the SOM case. A method is also presented to distinguish the parameter intervals leading to heterodyne and to zero-IF operation at both the lower and upper frequency bands. In the zero-IF SOM, the possible instantaneous unlocking in the presence of modulated input signals is investigated and avoided. The methods have been applied to a dual mixer at the frequencies 2.4 and 4.1 GHz.

A high‐efficiency design for 5‐W 2.4/5.8 GHz concurrent dual‐band class‐E power amplifier

AbstractIn this letter, a distributed element‐based load network is proposed for designing a high‐efficiency dual‐band (DB) 5‐W Class‐E power amplifier (PA), at two widely spaced frequencies of 2.4 and 5.8 GHz. This network consists of two different stages. The first stage deploys a flexible network configuration with crossed transmission lines (TLINs) to provide concurrent DB fundamental matching in a closed‐form derivation, which transforms the standard resistance of 50 Ω directly to the optimal complex impedances. By tolerating the combination of the up‐side and down‐side TLINs, the size of the overall circuit as well as the implementation complexity are reduced. The second stage uses a DB TLIN‐based resonator preceded by a series 50 Ω stub to control the harmonic impedances without altering the fundamental impedances, ensuring high efficiency at the fundamental frequencies. The measured prototype shows highest power added efficiency (PAE) of around 62.9% and 61.7% with output power of about 39 and 35 dBm at 2.45 and 5.76 GHz, respectively.

Modified indirect learning applied to neural network-based pre-distortion of a concurrent dual-band CMOS power amplifier

Current radio communication systems that adopt amplitude and phase modulations demand high linearity and high efficiency. The cascade connection between digital baseband pre-distorter (DPD) and power amplifier (PA) can be a cost-effective solution to guarantee the required linearity without compromising the efficiency. In the design of a DPD for a single band PA, direct learning can be used to extract the pre-inverse parameters or, alternatively, indirect learning can be employed by exchanging the position of the system during the identification procedure to avoid the necessity of a PA model within a closed-loop process. The performance of direct learning is substantially dependent on the accuracy of the behavioral model that replaces the PA. Furthermore, in a practical environment where only an approximation to the inverse is achieved, the linearization capability of the indirect learning is affected by shifting the post-inverse placed after the PA to a pre-inverse located before the PA. For concurrent dual-band PAs, an additional advantage of the indirect approach is that the post-inverse identifications for each band are completely independent of each other. In an authors’ previous work, a comparative analysis between the two learning architectures applied to the linearization of concurrent dual-band PAs was performed based on DPDs modeled by polynomials with memory. This work contributions are the extension of such comparative analysis to DPDs modeled by artificial neural networks, the development of complex-valued three-layer perceptrons suitable for concurrent-dual band DPDs and the introduction of a modified indirect approach to improve the accuracy of previous direct and indirect learnings. Spectre-RF transient simulations are performed in the circuit-under-test described by a wideband 130 nm CMOS PA concurrently stimulated by 2.4 GHz Wi-Fi and 3.5 GHz LTE signals. Reported simulation results show that, in a comparison with the previous direct and indirect learnings with similar output mean powers of about 60 mW, the modified indirect approach provides a superior linearity performance. The modified indirect learning reduces the error vector magnitude (EVM) metric to 0.87% and 1.13% for Wi-Fi and LTE bands, respectively, whereas the indirect and direct learnings achieve EVM equal to or larger than 1.05% and 1.49% for Wi-Fi and LTE bands, respectively.

A Low-Complexity Suboptimal Method for Two-Dimensional Crest Factor Reduction of Concurrent Dual-Band Signals

This letter proposes a low-complexity suboptimal two-dimensional crest factor reduction (2D-CFR) scheme for dual-band signals based on noise segment cancellation, which is approximated by combining the pulse kernel signals of two bands with the dual-band combining effect being taken into account. The proposed method reduces the calculation of fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) due to requiring no filtering. At the end of the letter, the computational complexity and performance of the algorithm are analysed and compared. The numerical results show that the computational complexity of the proposed solution is significantly reduced with similar error vector magnitude(EVM) performance as compared to traditional methods.

Design of a multimode tunable low noise amplifier for software defined radios

This Letter presents the design and analysis of a tunable low noise amplifier (LNA) capable of achieving single band, dual band and wideband operations. The circuit features a modified tunable open stub matching to achieve a reconfigurable multiband response. The LNA adopts a varactor diode in the input matching stage to achieve reconfigurable modes. Two bias conditions for the varactor diode are analysed. The forward bias condition yields a wideband mode (1.6 to 2.5 GHz) and zero bias results in a concurrent dual band mode (0.9 and 1.7–2.5 GHz). In reverse bias condition, the bias voltage of varactor diode () can be tuned to achieve one single band mode (1 GHz), and a tunable concurrent dual band mode, where the first band is fixed at 1 GHz and the second band is continuously tunable from 1.7 to 2.5 GHz. The LNA is fabricated in microwave integrated circuit process on an FR-4 board. The measured power gain is 7–15 dB and noise figure is 1.2–2.2 dB across all bands. The measured 1 dB compression () is , and at 0.9, 1 and 2.4 GHz, respectively.