Input Impedance Matching Research Articles

Printed dual‐band base station antenna for GSM/DCS/PCS/UMTS and LTE applications with dual polarization

SummaryA new design of the dual‐band and dual‐polarized base station antennas for supporting the mobile communication systems operating at the GSM/DCS/PCS/UMTS and LTE frequency bands is presented. A wide input impedance matching bandwidth is achieved due to a trident‐shaped feeding technique. Two printed dipoles, which are located perpendicularly to each other and fed by stepped‐microstrip lines, establish the proposed antenna. In addition, by locating a low‐profile cavity‐backed structure, as a metal reflector under the antenna, bidirectional radiations of the dipoles are switched to unidirectional radiations with an increase in the gain of the antenna. Measurement results indicate that the proposed antenna is suitable for base station applications at the operating frequencies of 800/900/1800/1900/2300 MHz. The isolation is better than 20 dB, and peak gains of 10.08 and 9.96 dBi are attained at port‐1 and port‐2, respectively. Furthermore, the HPBWs of the antenna in H‐plane is more than 61° for each port. The overall dimension of the antenna is 168 × 168 mm2, which is mounted upon a 222 × 222 mm2 cavity‐backed structure with a depth of 42 mm.

Zr doped Barium hexaferrite nanoplatelets and RGO fillers embedded Polyvinylidenefluoride composite films for electromagnetic interference shielding applications

In this study, we investigate the effect of M-Type zirconium doped barium hexaferrite nanoparticles addition with reduced graphene oxide (RGO) fillers in Polyvinylidenefluoride (PVDF) matrix to design lightweight and flexible polymer composite films for electromagnetic wave absorption and electromagnetic interference (EMI) shielding. Firstly, Zr doped M-Type barium hexaferrite (BaZrFe11O19) nanoparticles were prepared by sol-gel auto-combustion method and RGO by modified Hummers' method followed by thermal reduction process. PVDF/RGO/BaZrFe11O19 composite films were fabricated using simple solvent casting method. The resultant samples were investigated using various instruments including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman Spectroscopy, High resolution scanning electron microscopy (HRSEM), Energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and Vibrating sample magnetometer (VSM) analysis. The EMI shielding effectiveness (SE) of PVDF/RGO/10 wt% BaZrFe11O19 composites films is higher than that of PVDF/RGO/30 wt% BaZrFe11O19 composites in the X-band (8.2 GHz −12.4 GHz) frequency. Inclusion of BaZrFe11O19 nanoplatelets and conductive RGO fillers in the polymer PVDF matrix enhances shielding by conquered absorption with less reflection. The shielding mechanism suggests that in addition to conducting and magnetic losses due to RGO and BaZrFe11O19 respectively, the synergetic effect among RGO, BaZrFe11O19 and PVDF supports shielding by input impedance matching to that of free space, multiple internal reflections from BaZrFe11O19 and subsequent absorption by RGO, eddy current losses, dielectric losses, interfacial polarization losses, and so on. The resultant flexible films show an excellent EMI shielding efficiency (EMI SE) of 48.59 dB at 11.1 GHz for 10 wt% BaZrFe11O19 addition in polymer composite for a very small thickness of 0.2 mm. The higher dielectric loss (tanδε = 1.67) and magnetic loss (tanδμ = 0.41) contribute to the microwave absorption value of 40.98 dB (>99% attenuation) and are found to decrease with the amount of ferrite nanofillers. These results demonstrate that RGO and minimum amount of M-Type doped barium hexaferrite nanofillers embedded with polymer composite films could be one of the promising EMI shielding materials for RADAR and military applications.

A 350 mV, 280 μW 1.5-to-4.5-GHz wideband folded mixer adopting capacitive-cross-plus-magnetic-coupling

This paper describes a 1.5–4.5 GHz CMOS wideband mixer that operates from a single supply of 350 mV, allowing direct powering from various energy harvesting sources. The key techniques adopted for low power and low voltage operation are: (1) complementary transconductance stage in folded topology and current reuse, (2) forward body bias, and (3) gm-boosting by capacitor-cross and transformer coupled (CCTC). The CCTC achieves a high conversion gain (Gc) and a wideband input impedance matching under low power operation. Designed in 130-nm CMOS process, the mixer exhibits Gc of 12.2–16.4 dB and noise figure (NF) of 8.2–12 dB. The maximum input-referred 3rd-order intercept point (IIP3) is −11 dBm while consuming only 280 μW of power at an intermediate frequency (IF) of 50 MHz. The low power and low supply operation render the proposed CMOS mixer suitable for communication among multiple sensor nodes in a wireless body-area sensor network (WBAN).

A wideband blocker-resilient direct delta sigma receiver with selective input-impedance matching

This paper presents a wideband blocker-tolerant direct varDelta varSigma receiver (DDSR). Blockers are attenuated through selective input impedance matching and reduced gain design. The selective input impedance profile provides a low impedance at blocker frequencies enabling blocker attenuation, while the in-band impedance is boosted to matched condition through an up-converted positive feedback from the DDSR output. In addition, with the help of reduced gain design, near band blocker gain is minimized, further improving the blocker resilience. The receiver is designed for configurable operation from 0.7–2.7 GHz and a baseband bandwidth of 10 MHz. Simulated in a 28 nm technology, the DDSR demonstrates a maximum noise figure of 6.2 dB, and achieves a peak SNDR of 53 dB with an out-of-band 1 dB input compression point of -,11 dBm at a 100 MHz offset.

A 1-V 4-mW Differential-Folded Mixer With Common-Gate Transconductor Using Multiple Feedback Achieving 18.4-dB Conversion Gain, +12.5-dBm IIP3, and 8.5-dB NF

This article reports a novel differential-folded mixer with multiple-feedback techniques for performance enhancement. Specifically, we introduce the capacitor cross-coupled (CCC) common-gate (CG) transconductance stage to improve the noise figure (NF) at low power by boosting the effective transconductance, while enhancing the linearity via suppressing the second-order harmonic distortion. Typically, the created loop gain of the CCC can raise the third-order intermodulation (IM3) distortion, penalizing the input-referred third-order intercept point (IIP3). Here, we propose a positive and a second capacitive feedback into the CCC CG transconductor, not only to suppress the IM3 distortion current but also adds in design flexibility to the input transistors. Furthermore, the positive feedback also improves the input impedance matching, conversion gain, and NF through a flexible design criterion. Prototyped in a 0.13-μm process, the proposed mixer operating at 900 MHz dissipates 4 mW at 1 V. The measured double sideband (DSB) NF is 8.5 dB, the conversion gain (G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> ) is 18.4 dB and the IIP3 is +12.5 dBm.

A sharp‐selective micro strip triplexer with hairpin resonators for long‐term evolution (LTE)

SummaryA compact size planar micro strip triplexer for long‐term evolution (LTE) is presented. The triplexer consists of three hairpin band pass filters and a T‐shaped micro strip line. T‐shaped microstrip line has been used as input signal splitting structure and hairpin filters bring sharp selectivity. Input impedance matching of the structure carried out with three metalized vias in the middle of the filters. The central pass band frequencies (0.9, 1.17, and 1.5 GHz) are selected according to LTE frequency bands. The pass band of the filters include 0.88 to 0.91, 1.16 to 1.21, and 1.47 to 1.53 GHz. Isolation among the output channels are better than 40 dB. The measurement results verify the design process satisfactorily. The proposed triplexer can be used in BTS antenna for enabling more than one transmitter on a single antenna.

Simplified implementation of millimetre‐wave zero‐bias detector for an accurate detection in six‐port‐based receivers

In this Letter, a simplified design approach for zero-bias power detectors suited for integration in six-port receiver architectures is presented. The proposed concept uses the quadrature hybrid coupler as an effective way to improve the input impedance matching and linearity performance. The proposed solution has been experimentally validated through its implementation into a 60 GHz six-port receiver prototype to investigate its performance in detecting various M-ary quadrature amplitude modulation (M-QAM) signals. The obtained measurement results show a high accurate and linear detection responses for all investigated M-ary QAM modulation techniques (4-QAM, 16-QAM, 32-QAM). The variation in the error rates of the demodulated signals at the adjacent differential outputs is minimal (<1%), and the maximum error rate achieved does not exceed 5%. The obtained precision and linearity performances make the proposed structure highly suitable for the emerging millimetre-wave six-port receiver front-ends.

An Image Rejection Ku-Band CMOS Low Noise Amplifier With Bridged-Tee Band-Stop Filter

For satellite communication applications, this paper presents an image rejection Ku-band low noise amplifier (LNA) in a 65-nm CMOS process for the Hartley receiver architecture. To achieve high input/output linearity performance, the inductive source degenerated cascode and the capacitive neutralized common-source (CS) amplifier topologies are used in the LNA input and output stages, respectively. To achieve wideband input return loss, the minimum noise figure and high gain performance simultaneously, the inductive source degenerated cascode amplifier is co-designed with the fourth order input impedance matching network. For the image rejection purpose, a bridged-tee band-stop filter is proposed. The measurements show the LNA achieves 14.3-to-18.3 GHz 3 dB bandwidth with 17-to-20 dB power gain, 3.5-to-4 dB noise figure, 17-to-37 dB image rejection and -5 dBm IIP3. Including all pads, the chip occupies a silicon area of 1360 × 450 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and consumes 72 mW DC power.

A 3.15-mW +16.0-dBm IIP3 22-dB CG Inductively Source Degenerated Balun-LNA Mixer With Integrated Transformer-Based Gate Inductor and IM2 Injection Technique

This article proposes two linearization techniques in improving the third-order input intercept point (IIP3) of a balun-low-noise amplifier (LNA) mixer. First, the intrinsic third-order intermodulation (IM3) product of the inductively source degenerated (ISD) transconductor from the second-order derivative transconductance component ( ${g}''_{m}$ ) is reduced by tailoring toward the optimum biasing point at the moderate-inversion region. Second, the generated IM3 current by the first-order derivative transconductance ( ${g}'_{m}$ ) due to the interaction with the feedback component in the ISD transconductor is attenuated by second-harmonic injection via the bulk of the ISD transconductor. Furthermore, a transformer-based gate inductor and a transformer-based balun are applied to improve the input impedance matching and produce a balanced differential input signal. Measured results in 0.13- $\mu \text{m}$ CMOS show a high IIP3 of +16 dBm and a conversion gain (CG) of 22 dB at 2.4 GHz. The double-sideband (DSB) noise figure (NF) is 7.2 dB, and the power consumption is 3.15 mW at 1.2 V.

A switchable dual‐mode fully‐differential common‐source low‐noise amplifier in 0.18‐μm CMOS technology

AbstractA highly‐integrated switchable dual‐mode low‐noise amplifier (LNA) is proposed and implemented in standard 0.18 μm complementary metal‐oxide‐semiconductor (CMOS) technology for ultra‐high frequency‐radio‐frequency identification (UHF RFID) reader receivers. This dual‐mode LNA can be controlled to operate in two different modes in order to meet the requirements for the listen‐before‐talk mode and the normal mode of the UHF RFID reader receiver, respectively. The fully‐differential common‐source cascode topology with perfect input impedance matching, capacitive cross‐coupling, and common‐mode feedback techniques are employed to improve its performance. Measurement results show that, from a single power supply of 1.8 V, the LNA achieved the power gain (S21) of 9.1 dB, the input power reflection (S11) of −20 dB, the minimum noise figure (NF) of 3.6 dB, and the P1dB of −5 dBm in high‐gain mode. In high‐linearity mode, S21 of 3.2 dB, S11 of −17 dB, NF of 5.2 dB, and P1dB of −1.3 dBm were obtained.

Analysis and Optimization of Voltage-Driven Double-Balanced Passive Mixer for MICS Band Receiver

This paper presents analysis of a 25% duty-cycle fully-differential double-balanced passive mixer dedicated to medical implantable devices. The proposed passive mixer is part of a medical implant communication service (MICS) receiver front-end operating at 402–405[Formula: see text]MHz. By performing time-domain analysis, two LTI models have been developed to study the fully-differential double-balanced passive mixer: A simplified model and a complete model taking into account harmonic components. Both models account for the AC coupling capacitors at the mixer input and account for baseband voltage variation over one LO period. In this study it has been shown the ability of mixer input impedance matching by varying baseband resistor at the mixer output. The frequency of match can be controlled by varying the AC coupling capacitors and baseband capacitors. The performance of the proposed models was compared with that of the mixer and the results were very close. In particular, the results of simulations of the input impedance as a function of the baseband resistance and as a function of the IF frequency show the validity of the proposed models. The main parameters of the passive mixer such as input impedance, gain and noise figure (NF) were optimized taking into account the constraints of our application. The proposed mixer is designed to operate at LO frequency of 403.2[Formula: see text]MHz. Transistors size is optimized to meet the receiver specifications. The mixer realizes a conversion gain of 0[Formula: see text]dB and an NF of 4.8[Formula: see text]dB. Linearity simulations show 25.2[Formula: see text]dBm for IIP3 and 9.66[Formula: see text]dBm for [Formula: see text]dB. The mixer consumes 1.44[Formula: see text]pW without LO circuit.

A 2.99 dB NF 15.6 dB Gain 3-10GHz Ultra-wideband low-noise amplifier for UWB systems in 65 nm CMOS

A low noise figure (NF) and high power gain (S21) 3–10 GHz ultra-wideband (UWB) low noise amplifier (LNA) in 65 nm CMOS technology is proposed for UWB system which has a high figure of merit. A shunt–shunt resistive feedback technique is used to achieve wideband input impedance matching. A differential current-reused structure is used to achieve high common noise suppression and low power consumption. The implemented LNA achieves a high and flat aS21 of 15.6 ± 1.07 dB with an input return loss (S11) which is better than − 8.7 dB and a low NF of 2.99 ± 0.18 dB at frequencies of 3–10 GHz. The measured input third-order intermodulation point (IIP3) is − 5.7 dBm at 6 GHz.

Broadband Electromagnetic Response and Enhanced Microwave Absorption in Carbon Black and Magnetic Fe3O4 Nanoparticles Reinforced Polyvinylidenefluoride Composites

High-efficiency Electromagnetic Interference (EMI) shielding materials are essential in the harsh environment created by unwanted electromagnetic (EM) signals. In this work, polyvinylidenefluoride (PVDF) composites reinforced with magnetic Fe3O4 nanoparticles and cost-effective conducting carbon black (CB) were derived by a solution mixing and coagulation method. Coagulation is found to be an effective method to fabricate uniform composites of materials having higher tendency to form aggregates. The three-dimensionally extending conducting network created by CB and the hopping electrons from Fe3O4 result in high electrical conductivity of PVDF/CB/Fe3O4 composites (PCF). The permittivity, permeability and impedance spectra in the 10 MHz–1 GHz broadband region indicate that dielectric loss is dominating over magnetic loss and is attributed to the collection of a large number of capacitive regions at the interfaces formed by CB and Fe3O4, which results in the enhanced interfacial polarization losses in PCF composites. The composites exhibit EMI shielding effectiveness (EMI SE) greater than 20 dB and their shielding mechanisms involve dielectric losses, magnetic losses and their synergistic interaction. The matching input impedance of the composites allows the radiations to enter into the material and it undergoes multiple internal reflections at the interfaces and the energy of the internally reflected radiation is subsequently absorbed by CB. These different mechanisms result in an absorption dominated EMI shielding with a total EMI SE of 55.3 dB (99.9997% of shielding) for PCF-40 composite having thickness 2 mm and an average skin depth of 0.37 mm in the X-band microwave region.

Design and Analysis of a Broadband Current-Mode CMOS Direct-Conversion Receiver Frond-End Circuit

A broadband (0.8–5[Formula: see text]GHz) CMOS current-mode direct-conversion receiver has been integrated in a 0.18-[Formula: see text]m CMOS process. The proposed receiver front-end features a broadband active-balun low-noise transconductance amplifier (LNTA) driving a current-mode passive mixer terminated by a low-input-impedance transimpedance amplifier (TIA). The receiver chain has improved robustness to out-of-band interference, conversion gain and outstanding linearity. With the technique of noise and distortion cancellation which performs a better input impedance matching, we employ a broadband common-gate–common-source (CG–CS) LNTA and a current mirror to improve both gain and noise figure (NF) performance. Compared to the 50% duty-cycle switching stage, the 25% duty-cycle I–Q switching stage is implemented by using serial switches driven by 50% quadrature local oscillator (LO) signals separately, which improves the down-conversion gain by 3[Formula: see text]dB and lowers the noise figure. The transimpedance amplifier employs the [Formula: see text]-boosting technique to realize low input impedance and high transimpedance gain. The core circuit (RF and baseband signal path) consumes 26[Formula: see text]mW, and the prototype receiver achieves approximately 33–34.5-dB conversion gain, 8.1–9.35-dB NF and 7.5–9.8-dBm IIP3 from 0.8[Formula: see text]GHz to 5[Formula: see text]GHz.

A compact miniature fractal planar antenna for RFID readers

&lt;p&gt;This article presents a new miniature microstrip antenna in the ISM "Industrial Scientific and Medical" band, at 2.45 GHz. This microstrip antenna is designed for RFID reader system, by exploiting the fractal technique and the CPW fed; this antenna is printed on FR4 substrate with dielectric constant of 4.4. The validated antenna has a good matching input impedance range from 2.27 GHz to 2.68 GHz with a stable radiation pattern, a gain of 2.2 dBi, and a directivity of 1.91 dB. The total area of the final circuit is 21.22 x 32.05 mm2. A prototype of the proposed antenna has been fabricated and measured.&lt;/p&gt;

Multimode resonator‐assisted dual band notch UWB antenna with additional bluetooth resonance characteristics

A compact planar integrated ultra-wideband (UWB) and Bluetooth antenna are presented in this study. The basic radiator is circular in shape with a wide slit in it to accommodate a space optimised T-shaped stub for Bluetooth frequency band. The proposed antenna is CPW-fed with bevelled ground planes for the purpose of improvement in input impedance matching. A novel multimode resonator at the back of the substrate is responsible for the creation of two-notched band at 5.5 and 8.1 GHz. The antenna exhibits an operational bandwidth of 3.–12 GHz for UWB application. The proposed antenna also has Bluetooth resonance characteristics at 2.4 GHz. The overall size of the antenna is 14 × 32 × 1.59 mm 3 . The antenna has a peak realised gain of 4 dBi and a constant group delay. The radiation pattern is also stable throughout the operational bandwidth. A fabricated prototype is developed and tested. Results obtained from electromagnetic simulation, equivalent circuit model, and measurement are in good agreement.

A New Technique Using Axially Slotted Microstrip Line for Antenna Impedance Matching Designs

Abstract A new technique is presented for designing microstrip patch antennas with very good input impedance matching. The analysis is carried out for 1.78 GHz, 2.42 GHz and 3.46 GHz rectangular patch antennas printed on low-cost fiberglass substrates (FR-4), mounted on a ground plane and fed by a microstrip line. The antenna impedance matching is obtained using a slotted microstrip line feeder. The use of the proposed impedance matching technique showed considerable improvement from the reflection coefficient point of view, with reduction of about 20 dB at the resonant frequency, without modifying the original dimensions of the antenna patch elements or the width of the feeding microstrip line. Numerical characterization is carried out using Ansoft Designer software and iterative method WCIP. Prototypes are fabricated and measured, for validation purpose, showing good agreement when compared to simulated results.

Bandwidth enhancement of compact microstrip rectangular antennas for UWB applications

In this paper design of microstrip patch antennas are presented for ultra wideband (UWB) applications. The designed antennas have good matching input impedance in a wide frequency band covering the UWB frequency band which is defined by the FCC. The proposed antennas consist of rectangular patch which is fed by 50Ω microstrip line. These antennas are investigated and optimized by using CST microwave studio, they are validated by using another electromagnetic solver HFSS. The proposed antennas are designed and optimized taking into account the optimized of the ground by using Defected Ground Structure (DGS) in order to improve the frequency band of microstrip antenna. Hence, the impedance and surface current of the antenna structures are affected by DGS. As will be seen, the operation bandwidth of the proposed antennas is from 3 to 15 GHz (return loss≤-10 dB), corresponding to wide input impedance bandwidth (133.33%), with stable omnidirectional radiation patterns and important gain. A good agreement has been obtained between simulation and measurement results in term of bandwidth clearly show the validity of the proposed structures. These antennas are useful for UWB applications, may be able to potentially minimize frequency interference from many wireless technologies i.e WLAN, WiMAX. Details of the antennas have been investigated numerically and experimentally.

Low‐profile triple‐band microstrip antenna via sharing a single multi‐mode patch resonator

A low-profile microstrip patch antenna (MPA) operating in triple WLAN bands (2.4 /5.2 /5.8 GHz) with stable broadside radiation is proposed by employing TM10, TM12, and TM30 modes. Firstly, the TM12 mode of the MPA could be excited at around 5.8 GHz by properly selecting its dimensions. Meanwhile, a linear slot is etched out at the center of the radiating patch to transform the radiated fields of TM12 and TM30 modes into the broadside radiation with low sidelobe level. Secondly, the shorting pins are symmetrically loaded underneath the patch, aiming to improve the input impedance matching of TM10 mode and push up its resonant frequency to around 2.4 GHz. Thirdly, a pair of parallel slots is near the radiating edges of the patch radiator, thus extending the surface current distribution of TM30 mode and reallocating its resonant frequency to around 5.2 GHz. In final, the prototype antenna is fabricated and measured to validate its working principle. The results illustrate that this low-profile MPA makes these three radiative modes resonate at around 2.44, 5.22, and 5.82 GHz, respectively. Most importantly, a stable normal radiation pattern with low cross-polarisation and sidelobe levels is maintained for the proposed antenna as well.

Cascaded Boost‐Class‐E for rotary capacitive power transfer system

This paper presents a capacitive power transfer (CPT) system design for low-power rotary applications. The aim of a rotary CPT system is to be free of power cables so it can achieve 360 degrees of free rotation, while remaining simple and easy to clean. In this work, a class-E high-frequency inverter with second-order LC compensation is proposed to drive the rotary CPT system. An LC compensation circuit is applied on both stationary and rotating sides in order to maximise the power transfer by increasing the voltage across the coupling plates. By implementing the proposed technique, the Class-E LCCL rotary CPT system that is efficient and less sensitive to load variations can be achieved. A Boost converter is also proposed here to provide input impedance matching and tune the input power of the Class-E LCCL rotary CPT system. A 10 W multiple plate rotary CPT prototype based on cascaded Boost- Class E LCCL is designed and implemented to demonstrate efficient wireless power transfer (WPT) across the rotating load. The results reveal >76% power transfer efficiency is successfully achieved at 1 MHz operating frequency and with 7.67 W output power.