Order Intermodulation Products Research Articles

A Joint Design of Radar Sensing, Wireless Power Transfer, and Communication Based on Reconfigurable Software Defined Radio

This paper proposes a compact three-mode base station capable of performing radar sensing, communication, and wireless power transfer (WPT) in collaboration with indoor sensor networks. With regard to the wireless sensor node, the base station transmits two-tone signals in the downlink to support its operation and provides two-way communication. The sensor node sends uplink information through backscattering using the third order intermodulation (IM3) product of the rectification. In the radar mode, a single-tone continuous wave (CW) is used to monitor if there is a moving target in the static environment. If a speed is detected, the transmit signal to the node is stopped, while the single-tone CW excitation will continue until the speed of the target is zero, and then the base station transmits a stepped frequency continuous wave (SFCW) signal to measure the distance of the target. The repeat between the two radar waveforms continues until the target is undetectable within the detection range. The software defined radio PlutoSDR is adopted as the base station. The system can wirelessly supply power and bi-directionally communicate with a CO2 sensor node 2 m away. It gives a range resolution of 2.5 cm and a minimum detectable speed of 0.25 m/s in the radar mode.

Multi-Channel Receiver Nonlinearity Cancellation Using Channel Speculation Passing Algorithm

This brief investigates a linearization method for multi-channel receivers based on speculations over the decision symbols that are used to cancel out the third order harmonic distortions and inter-modulation products in a feedback scheme. Although the optimal solution requires joint speculations across all channels, we show that using only channel-by-channel speculation is sufficient to provide significant system improvement at a fraction of the complexity of the all-channel optimal solution. The output symbol from a channel is replaced by its speculative nearest constellation point and used by the following channels in an iterative fashion until the nonlinearity cancellation process minimizes the errors for all channels without jointly searching for the solution. Mathematical analysis showing fast convergence and low complexity of the proposed machine learning algorithm is provided. The simulation results of a 5-channel receiver with the proposed channel speculation passing (CSP) algorithm show the improvement in signal-to-noise and distortion ratio (SNDR) and bit error rate (BER).

L‐band high power solid‐state power amplifier for aerospace usage

This work presents the design, implementation, and experimental results of an L-band solid-state power amplifier (SSPA) developed for the next generation high-power transmitter for the space usage. The microwave frequency nircuit (MFC) is realized by cascading a channel amplifier, a drive power amplifier (PA) and a high PA section. By utilizing the gallium nitride (GaN) HEMTs, the efficiency of the drive PA and high PA are improved to more than 70% over the frequency range from 1.45 to 1.55 GHz, which ensures an overall efficiency of the MFC higher than 66%. Then a high efficiency power-supply based on the phase-array bridge topology is proposed for voltage conversion and output sequence control, which delivers a high efficiency of about 94% at the rated power range. In the 100-MHz operating bandwidth, the SSPA delivers more than 200 W of output power with an associated 3rd order intermodulation product (IM3) and power added efficiency (PAE) better than −18 dBc and 60%, respectively. The gain can be varied from 25 to 56 dB with a minimal step of 0.5 dB through telecommand, whereas the phase can be adjusted within 360° range with a minimal step of 5.6°.

A fully matched dual stage CMOS power amplifier with integrated passive linearizer attaining 23 db gain, 40% PAE and 28 DBM OIP3

PurposeThe purpose of this paper is to introduce a new linearization technique known as the passive linearizer technique which does not affect the power added efficiency (PAE) while maintaining a power gain of more than 20 dB for complementary metal oxide semiconductor (CMOS) power amplifier (PA).Design/methodology/approachThe linearization mechanism is executed with an aid of a passive linearizer implemented at the gate of the main amplifier to minimize the effect of Cgs capacitance through the generation of opposite phase response at the main amplifier. The inductor-less output matching network presents an almost lossless output matching network which contributes to high gain, PAE and output power. The linearity performance is improved without the penalty of power consumption, power gain and stability.FindingsWith this topology, the PA delivers more than 20 dB gain for the Bluetooth Low Energy (BLE) Band from 2.4 GHz to 2.5 GHz with a supply headroom of 1.8 V. At the center frequency of 2.45 GHz, the PA exhibits a gain of 23.3 dB with corresponding peak PAE of 40.11% at a maximum output power of 14.3 dBm. At a maximum linear output power of 12.7 dBm, a PAE of 37.3% has been achieved with a peak third order intermodulation product of 28.04 dBm with a power consumption of 50.58 mW. This corresponds to ACLR of – 20 dBc, thus qualifying the PA to operate for BLE operation.Practical implicationsThe proposed technique is able to boost up the efficiency and output power, as well as linearize the PA closer to 1 dB compression point. This reduces the trade-off between linear output power and PAE in CMOS PA design.Originality/valueThe proposed CMOS PA can be integrated comfortably to a BLE transmitter, allowing it to reduce the transceiver’s overall power consumption.

An 800 MHz-to-3.3 GHz 20-MHz Channel Bandwidth WPD CMOS Power Amplifier For Multiband Uplink Radio Transceivers

This brief describes a novel Wideband Pre-Distortion (WPD) mechanism as a linearization technique for bandwidth-limited CMOS power amplifiers (PAs). The WPD comprises a common-source amplifier and a hybrid feedback mechanism blended with both active and passive networks to secure a flat gain response from 800 MHz till 3.3 GHz, while maintaining >30% power added efficiency (PAE) at a maximum linear output power of 20 dBm throughout the band of operation. The WPD generates unique gain and phase cancellation mechanisms on-chip therefore alleviating the 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> -order intermodulation product (IMD <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) for an operating bandwidth of 2.5 GHz. Measurement results on 180 nm CMOS, with a supply voltage of 3.3 V indicate that the WPD-PA produces a saturated output power of 24 dBm, in addition to a power gain of 15.5 dB and a peak efficiency of 35.5% at 2.45 GHz. The WPD-PA delivers a maximum linear output power of 20-dBm with an adjacent channel leakage ratio (ACLR) of -30 dBc and error vector magnitude (EVM) of 3.42%, 2.34% and 2.76% at 0.8, 2.45 and 3.3 GHz when measured with the 20-MHz LTE signal. The corresponding maximum linear PAE ranged between 31 to 34%. The chip area is 1.28 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Carrier to Intermodulation (C/I ratio) Calculations of a GaN 10W Class AB Power Amplifier

This article presents the analysis and design of a circuit to generate 3rd- order intermodulation (IM3) products for a GaN 10W Class AB power amplifiers (PA), The intermodulation products can’t be eliminated by filters. So, it’s a critical problem to resolve in RF systems. The circuit has been studied using a two-tone signal at a center frequency of 3.7 GHz. The two tones test is applied to make a large signal analysis of the RF power amplifier. For this paper, the two frequencies are at (3.7 0.005) GHz. The (C/I) ratio, is chosen to investigate the power amplifier non-linearity, and due to various causes, upper_C/I and lower_C/I, can be distinct.

Exploiting Sensitivity Enhancement in Micro-wave Planar Sensors Using Intermodulation Products With Phase Noise Analysis

In this paper, a new technique to enhance the sensitivity of microwave resonators is introduced. Double split ring resonators are implemented as the core of a loss-compensated resonator. It is illustrated that regenerative oscillators when mixed together can produce higher order intermodulation products (IMP) at the output. The variations in sensing tone are multiplied and exhibit considerably higher sensitivities at 3rd, 5th, and 7th IMP components compared to the main resonant frequency. The sensor is also integrated into wireless platform with ultra-wideband bowtie antennas. Common fluids such as Toluene, n-Heptane, IPA, Ethanol, Methanol, Acetone, and Water are tested in fluidic channel and demonstrated that the sensitivity for intermodulation products are significantly increased proportional to the order of IMP. The proposed sensor is also examined with glucose concentration sensing for the range of 0– 600 mg/dL and significant variation for 7th IMP sensor is observed as opposed to saturation of conventional sensor. Also, asphaltene concentrations down to 6 ppm are recognizable when precipitated from toluene solution using the proposed sensor. Moreover, a rigorous analytical study is presented for phase noise of the IMP originated from reference signals.

Comparison Between Analog Radio-Over-Fiber and Sigma Delta Modulated Radio-Over-Fiber

With the continuously increasing demand of cost effective, broadband wireless access, radio-over-fiber (RoF) starts to gain more and more momentum. Various techniques already exist, using analog (ARoF) or digitized (DRoF) radio signals over fiber; each with their own advantages and disadvantages. By transmitting a sigma delta modulated signal over fiber (SDoF), a similar immunity to impairments as DRoF can be obtained while maintaining the low complexity of ARoF. This letter describes a detailed experimental comparison between ARoF and SDoF that quantifies the improvement in linearity and error vector magnitude (EVM) of SDoF over ARoF. The experiments were carried out using a 16-QAM constellation with a baudrate from 20 to 125 MBd modulated on a central carrier frequency of 1 GHz. The sigma delta modulator runs at 8 or 13.5 Gbps. A high-speed vertical-cavity surface-emitting laser (VCSEL) operating at 850 nm is used to transmit the signal over 200-m multimode fiber. The receiver amplifies the electrical signals and subsequently filters to recover the original RF signal. Compared with ARoF, improvements exceeding 40 dB were measured on the third order intermodulation products when SDoF was employed, the EVM improves between 2.4 and 7.1 dB.

Development of Wideband and High IIP3 Millimeter-Wave Mixers

This paper presents the design and development of highly linear, wide bandwidth mixers. We propose a linearization technique that combines the optimum drain bias condition and multiple-gated transistors for resistive mixers. An on-chip three-line edge-coupled Marchand balun is designed to have low phase and amplitude imbalance for canceling out the even order intermodulation products. Two mixer prototypes: a single-balanced (SB) mixer and a double-balanced (DB) mixer are designed to prove the concepts. The experimental results demonstrate that the SB prototype mixer has a measured conversion loss of less than 11 dB and third-order input intercept point (IIP3) range of 27–33 dBm at 15-dBm LO drive from 7 to 34 GHz. The DB mixer exhibits a conversion loss of less than 11 dB and IIP3 range of 31–35 dBm from 7–26 GHz at 17-dBm LO drive. Both prototypes achieve a high port-to-port isolation of over 30 dB within the operation bandwidth. To the best of our knowledge, the mixers have the highest linearity over the widest bandwidth ever reported.

Highly linear reconfigurable UWB filters with independently controlled dual bandnotch

ABSTRACTThis letter proposes a high‐linearity reconfigurable lower ultra‐wideband (3.1–5.25 GHz) filter with independently controlled dual bandnotch at WiMAX 3.5 GHz band and satellite communication systems 4.2 GHz band. Reconfigurability has been achieved by the implementation of Graphene based switches (simulation only) and PIN diodes (measurements). The simulation and measurement results in OFF state show an entire bandpass response from 3.1 GHz to 5.25 GHz and with a very low insertion loss. In ON state, the results show that sharp rejections at 3.5 GHz and 4.2 GHz are achieved, with a low passband insertion loss. The two bandnotch operate independently of each other; thus allowing to control the behaviour of the required bandnotch. The third order intermodulation products were also measured in OFF and ON states and the linearity results have been presented. The filter is able to achieve a high performance with good linearity and no significant loss. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2639–2643, 2016

A two-tone test for characterizing nonlinear dynamic effects of radio frequency amplifiers in different amplitude regions

A new two-tone test method for radio frequency power amplifiers is presented. The test signal is a two-tone probing-signal superimposed on large-signals of different amplitude. The amplifier is, thus, excited in different amplitude regions. The amplitude and phase of the 3rd order intermodulation (IM) products are measured vs. frequency spacing and probing-signal amplitude in each region. The IM magnitude is a measure of the nonlinearity, while the frequency dependence and asymmetry are measures of the memory effects in the different regions. A Doherty and a class-AB amplifier were tested. For both amplifiers the IM magnitude increased by ∼15dB from the lowest to the highest amplitude region. For the Doherty amplifier the behavior of the IM products vs. frequency spacing was similar in all regions, indicating similar memory effects. For the class-AB amplifier the IM vs. frequency spacing was significantly different in the different regions, which indicates different memory effects.

An IM2-free floating current buffer using average power based automatic calibration for IEEE 802.15.6 transmitter

To meet the stringent spectral mask requirement of IEEE 802.15.6, a novel spectral shaping buffer and a new automatic calibration are proposed in this paper. By introducing a floating current into buffer, second order intermodulation product (IM2) is cancelled at output. To calibrate buffer, analog signal processing methods for average power extraction of residual IM2 and accurate quantization are presented, along with error-tolerant decision making logic. A sample human body communication (HBC) transmitter is designed in 0.13 µm CMOS process. Simulation results show spectral mask is suppressed below −120 dBr, satisfying the IEEE 802.15.6 standard specification.

CMOS upconversion mixer with filterless carrier feedthrough cancelation and output power tuning

The synthesis, design and implementation of a CMOS upconversion mixer that both can adjust, by means of a DC voltage control, its output power and that cancels the carrier feedthrough is presented. Aiming at very low cost medical implant applications, a prototype of the architecture was implemented in a double poly, three metal layers, 0.5μm CMOS technology. For a range between one half and one fifth of the supply voltage, the circuit can decrease in a quadratic form the power delivered to the load until one forth of its maximum value by varying the DC component at the baseband signal. In addition, a large IIP3 is attained since the closest high order intermodulation product present in the spectrum of the signal is far from the vicinity of the component of interest.

Simultaneous reduction of IMD3 and IMD5 in bisection laser diode by feedback second harmonic injection

This paper reports a scheme for reducing third and fifth order intermodulation distortion in 1.3µm gain lever laser diode. Third and fifth order intermodulation components are reduced in the laser diode output by second harmonic frequency signals which are extracted from the laser diode itself. The number of RF components required in the linearization circuit for distortion reduction is significantly reduced in this scheme. The active region of the laser diode is split into two sections at a ratio of 0.97:0.03 for realizing gain lever effect. The longer and shorter section currents are fixed as 20mA and 5mA, respectively, corresponding to maximum gain lever. The rate equation approach is used for the analysis. In this scheme, third and fifth order intermodulation components are simultaneously reduced, by injecting second harmonic of two tone signals with appropriate amplitude and phase. A 14.7dB and 9.4dB improvement in third order and fifth order intermodulation respectively, are predicted at 2.4GHz. The magnitudes of third and fifth order intermodulation products are calculated from analytical expressions and the results are found to agree with simulation. Further the effect of RF carrier frequency and channel spacing on distortion reduction is also investigated.

Gain, noise and intermodulation in a nonlinear superconducting resonator

A superconducting microwave resonator is modified with several weak links to make it nonlinear and operated as a phase-insensitive microwave amplifier. Signal gain is demonstrated by intermodulation with a strong pump. The gain is sharply frequency dependent, and we demonstrate phase dependence by examining correlations between the signal and one idler which is a 3rd order intermodulation product of the pump and signal tones. A calibration procedure is described which is based on measurement of both thermal and quantum noise, revealing that the following HEMT amplifier adds noise at 15 times the quantum limit. When operated as a phase-insensitive amplifier the nonlinear resonator added noise at 2.5 times the quantum limit. Significant power is found at intermodulation products beyond 3rd order, which may be responsible for the inability to reach the quantum limit.PACS Codes: 74.78.-w, 42.65.Yj, 85.25.Cp.

Analysis on Reverse Intermodulation Generated by Co-Siting Multi Standard Base Stations

The reverse intermodulation interference exits among multi-standard base stations, it needs less than-114dBm/100KHz within a receiver band. A test method improved mechanism to measure IM3 (3rd order intermodulation product) during base station design, which made the test results better by reducing the nonlinear contribution from key component directional coupler in test environment. The new method changed hardware connection without any cost. Improved test mechanism can detect low level IM3 beneath-138dBm/100KHz in RX band.

Image-rejection receiver using on-chip active notch filters for 2.4-GHz band wireless communication applications

This paper presents the design and experimental results of image-rejection (IR) receiver front-end for 2.4-GHz band applications. The proposed IR-receiver front-end integrates a third-order active notch filter into each of conventional cascode low noise amplifier and down-conversion mixer to achieve high image-rejection ratio (IRR). The image signal is suppressed and the wanted signal is maximized due to series and parallel resonator effects of the notch filter, respectively. Consequently, the proposed IR-receiver front-end implemented in a standard 0.18 μm CMOS technology has the power gain of 21.5 dB, the noise figure of 3.5 dB, the input third order intermodulation product of ?15 dBm and the IRR of 56 dB. The IR-receiver front-end dissipates a total of 5.5 mA from supply voltage of 1.8 V.

Successive Regeneration and Adaptive Cancellation of Higher Order Intermodulation Products in RF Receivers

In this paper, a general framework for the adaptive feedforward cancellation of higher order intermodulation distortion (IMD) products is presented. By generating only second-order and principal-odd-order IMD reference products in the RF/analog domain and reproducing higher order IMD reference products at digital baseband, the proposed reference distortion scheme minimizes the analog hardware burden on the system. Inherent in this procedure is an approximation that the profile of blocking signals causing IMD is dominated by one very large blocker. The limitations imposed by this approximation are quantitatively examined and shown to permit cancellation ratios of nearly the square of the ratio between the dominant and nondominant blocking signal RMS amplitudes. An experimental receiver employing the proposed technique was constructed utilizing a wide-swing low-noise transconductance amplifier in order to accommodate a rail-to-rail (+12.4 dBm) out-of-band blocker and a -16.3-dBm nondominant blocker. The measured receiver out-of-band 1-dB desensitization point is +12.5 dBm and the peak uncorrected two-tone third-order intermodulation intercept point (IIP3) is +33.5 dBm. Utilizing the proposed IMD cancellation scheme in the presence of a modulated dominant blocker improves the total input-referred IMD error power by over 24 dB, resulting in an extrapolated IIP3 metric of +43.5 dBm.

DESIGN OF A MICROSTRIP BALANCED MIXER FOR SATELLITE COMMUNICATION

The design and measured results of a compact, low cost, low conversion loss microstrip single balanced Schottky diodes mixer is proposed. This mixer is designed for Ka-band satellite transponder simulator to convert the 30GHz radio-frequency (RF) signal down to the 20GHz intermediate-frequency (IF) signal with 9.8GHz local oscillator (LO) frequency. This design takes full advantage of the frequency relationship of the RF, IF and LO, which is 3 : 2 : 1. A microstrip rat-race ring is designed at the LO frequency, which also functions as a 180-degree hybrid coupler at the RF frequency by its intrinsic multi-band characteristic. The amplitude and phase balance at both LO and RF frequency are analyzed, which guarantee the state- of-art performance of this single balanced mixer. The multi-function open/short stubs and a lowpass fllter (LPF) with bonding wires across the rat-race ring are optimized to realize this low conversion loss mixer. The measured results show that the conversion loss is less than 9dB at the IF frequency from 20.0 to 21.6GHz, and the power of the second harmonic of LO is i45dBm with +6:5dBm LO drive power. The 3rd order inter-modulation products (IMD3) could be lower than i50dBc with LO power higher than +7:8dBm at the input RF power of i15dBm.

Intermodulation and harmonic distortion in slow light Microwave Photonic phase shifters based on Coherent Population Oscillations in SOAs

We theoretically and experimentally evaluate the propagation, generation and amplification of signal, harmonic and intermodulation distortion terms inside a Semiconductor Optical Amplifier (SOA) under Coherent Population Oscillation (CPO) regime. For that purpose, we present a general optical field model, valid for any arbitrarily-spaced radiofrequency tones, which is necessary to correctly describe the operation of CPO based slow light Microwave Photonic phase shifters which comprise an electrooptic modulator and a SOA followed by an optical filter and supplements another recently published for true time delay operation based on the propagation of optical intensities. The phase shifter performance has been evaluated in terms of the nonlinear distortion up to 3rd order, for a modulating signal constituted of two tones, in function of the electrooptic modulator input RF power and the SOA input optical power, obtaining a very good agreement between theoretical and experimental results. A complete theoretical spectral analysis is also presented which shows that under small signal operation conditions, the 3rd order intermodulation products at 2Ω1 + Ω2 and 2Ω2 + Ω1 experience a power dip/phase transition characteristic of the fundamental tones phase shifting operation.