Microwave Active Filters Research Articles

Дослідження температурної нестабільності в активних НВЧ фільтрах та методи її зменшення

The article presents a study of methods for reducing temperature instability in active microwave filters. The analysis of the effect of temperature on the parameters of an active microwave filter is carried out. The results of experimental studies of the temperature characteristics of microwave filters are also presented. When designing digital systems, especially modern ones that operate with a clock frequency or that use a radio channel in the microwave and microwave range, there is usually a problem of increasing the reliability or reducing the overall size while maintaining high electrical parameters. Requirements for miniaturization of microwave equipment, the task is to create filter circuits that are suitable for integrated production. Unlike low-frequency active filters, when constructing microwave filters, it is necessary to take into account the inertial properties of transistors. Therefore, studies of various stripe active microwave filter circuits exploit reactive phenomena in the transistor. The possibility of their temperature and dynamic stabilization by changing the emitter current of a bipolar transistor is shown. Various circuit solutions for the implementation of this method are proposed. As experimental studies have shown, with increasing temperature, there is a decrease in the filter transfer coefficient at the quasi-resonant frequency. Experimental studies have shown that in order to stabilize the transfer coefficient of temperature rise, an increase in the emitter current is necessary, which can be achieved by a general increase in the supply voltage. Thus, for thermal stabilization of the frequency response of the microwave filter, it is necessary to regulate the current of the transistor emitter simultaneously with the temperature change. The magnitude of the emitter current adjustment when the temperature changes from –60 °C to +100 °C is 3—4 orders of magnitude for low-power silicon transistors.

Design of a CMOS-based microwave active channelized bandpass filter

A two-branch microwave active bandpass filter is designed through the channelized filtering technique as well as the transversal concept. Both the main and the auxiliary branches, connected without power dividers/combiners, rely on C-coupled active third order Chebyshev bandpass filters. A lumped element signal delay circuit is also introduced in the main channel. Active inductors based on the gyrator-C topology, are involved in the Chebyshev filters’ structure. CMOS-based Operational Transconductor Amplifier (OTA) circuits are the building blocks of these inductors. The proposed active transversal channelized filter produces an elliptic narrow band response, centered at 1.13 GHz. Simulation results, obtained by means of the PSPICE code according to the 0.18 μm TSMC MOS technology, indicate excellent performances illustrating good impedance matching, low insertion losses and high selectivity. Finally, the noise analysis shows that the filter has a low noise figure in the bandwidth.

Design of active inductor-based butterworth and chebyshev microwave bandpass filters in standard 0.18µm-CMOS technology

In this paper we propose a synthesis of microwave active filters having Butterworth and Chebyshev responses in the frequency range 1GHz-2GHz. The filter fundamental block, used to build an active inductor, consists of CMOS-based Operational Transconductance Amplifier (OTA) circuits. These amplifiers are made out of simple current mirror using MOS transistors. The simulation procedure has been carried out through PSPICE software showing good performances regarding scattering parameters in terms insertion losses, of out-of-band rejection and phase.

A microwave active filter for nanosatellite’s receiver front-ends at s-bands

<p>In satellite technology, the communication between space segment and ground segment plays a vital role in the success of the mission. This paper is targeted at study, design and fabrication of a microwave active filter for the receiver front-ends using coupled line filter structure, which can be applied to the nanosatellite’s communication subsystem. The whole active filter module is a combination of a microstrip bandpass filter and a preceding two-stage wideband low noise amplifier using FET devices. The proposed module operates in the frequency range of 2 - 2.4 GHz, which can be divided to 10 frequency slots of about 40 MHz for each. These frequency slots will be used for the S-band multi-frequency receiving function of the ground station, as well as the nanosatellite. The simulated and measured results of this active filter configuration are presented.</p>

Design of active inductor-based butterworth and chebyshev microwave bandpass filters in standard 0.18µm-CMOS technology

<p>In this paper we propose a synthesis of microwave active filters having Butterworth and Chebyshev responses in the frequency range 1GHz-2GHz. The filter fundamental block, used to build an active inductor, consists of CMOS-based Operational Transconductance Amplifier (OTA) circuits. These amplifiers are made out of simple current mirror using MOS transistors. The simulation procedure has been carried out through PSPICE software showing good performances regarding scattering parameters in terms insertion losses, of out-of-band rejection and phase.</p>

Research, design and fabrication of a microwave active filter for nanosatellite’s receiver front-ends at s-band

In satellite technology, the communication between space segment and ground segment plays a vital role in the success of the mission. This paper is targeted at study, design and fabrication of a microwave active filter for the receiver front-ends using coupled line filter structure, which can be applied to the nanosatellite’s communication subsystem. The whole active filter module is a combination of a microstrip bandpass filter and a preceding two-stage wideband low noise amplifier using FET devices. The proposed module operates in the frequency range of 2-2.4 GHz, which can be divided to 10 frequency slots of about 40 MHz for each. These frequency slots will be used for the S-band multi-frequency receiving function of the ground station, as well as the nanosatellite. The simulated and measured results of this active filter configuration are presented.

Dual-tunable multiferroic active ring filter for microwave photonic oscillators

A theoretical model of a microwave active ring filter based on a ferrite-ferroelectric layered structure serving as a waveguide for spin-electromagnetic waves is developed. An experimental prototype of the device is fabricated and characterized. The device is implemented as an active-ring resonator with a microwave amplifier and a ferrite-ferroelectric delay line. The resonance properties of this system are studied theoretically and experimentally. The results show dual control of central frequency of the filter with magnetic and electric fields. An effective Q-factor of 50 000 and tuning by 5 MHz with an electric field are achieved at 8 GHz.

Novel MMIC architectures of wideband microwave active filters for frequency tuning and bandwidth multiplexing

AbstractThis article reports on novel architectures for designing tunable microwave active bandpass filters in monolithic microwave integrated circuit (MMIC) technology.The first two MMICs illustrate a specific synthesis method of microwave active bandpass filters and its extension to the frequency tunability, both were designed using the UMS PH25 process (UMS foundry; 0.25 μm GaAs p‐type high electron mobility transistor (pHEMT)). The third MMIC chip, designed using the OMMIC ED02AH process (OMMIC foundry; 0.2 μm GaAs pHEMT), illustrates a new application of the previous synthesis method, and concerns the design of an active filter allowing bandwidth multiplexing. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2680–2689, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26347

Design procedure for active microwave filters using the high quality active negative capacitance circuit for RF low‐noise bandpass applications

AbstractThis article presents a new methodology based on active band pass filter. In the proposed design, a resonator consists of an active negative capacitor together with a conventional inductor represented. The active negative capacitor is made of a field‐effect transistor that exhibits negative capacitance and negative resistance. It can, therefore, compensate the loss of an inductor. Two pole active bandpass filter centered 1.3 GHz, with 3 dB bandwidth of 640 MHz, high gain 1.5 dB, including a very low‐noise active filter which exhibits a noise figure of 2.5 dB are realized in the fist part. Compared with the conventional BPF, the proposed design shows better gain, noise figure, and the return loss level. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1086–1093, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23296

Recent advances in microwave active filter design. Part 1: Low-frequency techniques and noise optimization

This two-part article presents a representative sample of recent advances in microwave active filter design. In part one, we discuss design techniques based on both analog and digital low-frequency methods that have been adapted to microwaves. From circuits with analog origins, we present simulated results, with some experimental verification, for a frequency-dependent negative resistance (FDNR) and active-inductance MMIC bandpass filters. From circuits with digital origins, we present experimental results for recursive filters, including MMIC bandpass and bandstop structures as well as higher-order cascaded sections. Part one concludes with a discussion of the noise-wave formalism and experimental results for active-recursive and tunable ring-resonator filters with minimum noise figure. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 159–176, 2002.

Recent advances in microwave active filter design. Part 2: Tunable structures and frequency control techniques

This two-part paper presents a representative sample of recent advances in microwave active filter design. In the second part, we discuss design techniques for tunable structures and frequency control. First, we present switchable and continuously-tunable bandstop filters employing MMIC negative resistances to compensate for losses. Next, we detail several approaches to the design of tunable high-order “recursive-like” filters. Layouts and measurements are given for different MMIC implementations, with simulated results presented in other instances. Finally, we discuss new technologies and processes for future low-cost, low-noise microwave MMIC active functions. The article concludes with the description of a development, including experimental results, of frequency-control techniques based on locked-loop architectures. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 177–189, 2002.

A new design concept for wideband frequency-tunable and high-order MMIC microwave active recursive filters

This paper describes a new original microwave filter design concept using recursive principles and fully integrable in MMIC technology. To validate this technique, a 7 GHz fixed center frequency filter with 2% bandwidth and a tunable filter with 2.5 GHz tuning range around 8 GHz have been successfully implemented employing a 0.2 μm GaAs P-HEMT monolithic technology. A multicellular approach, using a cascade association of first-order recursive cells, is also described. A tunable two-pole filter has then been realized by a cascade association of two tunable one-pole filters. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 380–385, 2000.

Theoretical and experimental implementation of microwave active filters using automatic frequency control techniques

This paper discusses phase-locked loop (PLL) and magnitude-locked loop (MLL) techniques based on a voltage-controlled filter (VCF) for the automatic frequency control (AFC) of active filters. Applications to a microwave planar filter are considered. Theoretical analysis and simulated and measured results are presented for both phase and magnitude control circuits, enabling the filter to accurately track a reference signal. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 23–27, 2000.

Analysis and optimization of noise performance for various topologies of microwave active recursive filters using noise wave techniques

Analysis and optimization of noise performance for various topologies of microwave active recursive filters using noise wave techniques

Analysis and optimization of noise performance for various topologies of microwave active recursive filters using noise wave techniques

Analysis and optimization of noise performance for various topologies of microwave active recursive filters using noise wave techniques

Noise wave techniques analysis applied to various planar microwave active filter topologies

This article deals with the improvement of noise figure for various topologies of microwave active filters. We show how, using a noise wave formalism, the noise factor of different filters can be analytically derived and effectively minimized. We validate our approach with simulated examples for each topology. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 116–130, 1998.

Noise wave techniques analysis applied to various planar microwave active filter topologies

Noise wave techniques analysis applied to various planar microwave active filter topologies

Intermodulation distortion in active microwave filters

Active microwave filters have potential application in high-volume consumer products such as cellular-radio handsets. Active negative-resistance circuits may be coupled into physically small low-Q-factor filter structures to cancel resonator losses and produce apparently ideal filter characteristics. However, at large input-signal levels, the nonlinear active devices cause distortion effects, particularly with multiple signal inputs. Results from an experimental and computer-simulation study of saturation and intermodulation distortion in active negative-resistance microwave bandpass and bandstop filters are presented. These results have been generalised into simple formulas to enable the designer to determine the level of distortion in any specific filter of this type.

Optimization of noise performance for various topologies of planar microwave active filters using noise wave techniques

In this paper, two types of microwave active filters are studied. First we show how, using a noise wave formalism, the noise factor of three topologies of active recursive filters can be effectively minimized by using appropriate unbalanced power dividers/combiners and an amplifier. A comparison between the different topologies is given. Simulations and practical results are presented and validate our approach. In a second part, the noise wave formalism is applied to /spl lambda//2 microstrip active filters. We show how the appropriate choice of coupling between lines and resonators can achieve low-noise filters. Simulations and practical results are also presented.

Microwave active resonator band-pass filters in various mmic technologies

Cet article presente deux topologies de resonateurs actifs a circuits LC paralleles trois transistors, en technologie MESFET, HEMT ou HBT. Il montre la possibilite, en agissant sur la valeur d’une resistance et/ou d’une capacite, d’une part de fixer la frequence de resonance de ces circuits paralleles, et d’autre part de reduire leurs pertes jusqu’a obtenir une conductance negative. Ces resonateurs MMIC sont ensuite utilises pour synthetiser des reseaux compacts de filtrage en echelle, de bande etroite et sans pertes. Tandis que l’utilisation d’une technologie mmic a base de transistors mesfet avait restreint, jusqu ’a present, la synthese de ce type de filtres aux frequences de la bande S et aux frequences basses de la bande X, l’emploi de transistors HEMT et HBT permet d’etendre leurs realisations a toute la bande X. Cette etude est illustree par la simulation d’un filtre centre sur 10 GHz, de bande passante 500 MHz, realise a partir d’une technologie hemt 0,2 [un. La reponse du filtre presente un gain de 0,5 dB et des pertes par retour meilleures que 10 dB dans la bande passante.