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This paper aims to give an overview about the state of the art and novel technologies used in gas sensing. It also discusses the miniaturization potential of some of these technologies in a comparative way.

In this article, the authors state the most of the methods used in gas sensing discuss their advantages and disadvantages and at last the authors discuss the ability of their miniaturization comparing between them in terms of their sensing parameters like sensitivity, selectivity and cost.

In this article, the authors will try to cover most of the important methods used in gas sensing and their recent developments. The authors will also discuss their miniaturization potential trying to find the best candidate among the different types for the aim of miniaturization.

In this article, the authors will review most of the methods used in gas sensing and discuss their miniaturization potential delimiting the research to a certain type of technology or application.

Approaches for a miniaturisation of electrical machines that are based on an electromagnetic principle have to overcome numerous challenges. Some of these are only a result of the rules of growth (or shrinkage), some are a result of the micro technological fabrication processes. This paper aims to give an overview of the current state of the art including various examples of linear and rotating micro actuators that have been realised.

The paper presents details of further miniaturisation by using thin film technology for depositing and structuring soft magnetic and hard magnetic material as well as copper for conductors and insulation.

There are numerous limitations for the miniaturisation with respect to material properties, friction/guidance, etc. and this paper illustrates ways to overcome these limitations.

The paper presents a compact overview on the achievements gained in 12 years of research within a collaborative research centre of the German DFG.

Metamaterial unit cells composed of deep subwavelength resonators brought up new aspects to the antenna miniaturization problem. The paper experimentally demonstrates a metamaterial-inspired miniaturization method for circular patch antennas. In the proposed layouts, the space between the patch and the ground plane is filled with a proper metamaterial composed of either multiple split-ring or spiral resonators (SRs). The authors have manufactured two different patch antennas, achieving an electrical size of λ/3.69 and λ/8.26, respectively. The paper aims to discuss these issues.

The operation of such a radiative component has been predicted by using a simple theoretical formulation based on the cavity model. The experimental characterization of the antenna has been performed by using a HP8510C vector network analyzer, standard horn antennas, automated rotary stages, coaxial cables with 50 Ω characteristic impedance and absorbers. Before the characterization measurements we performed a full two-port calibration.

Electrically small circular patch antennas loaded with single layer metamaterials experimentally demonstrated to acceptable figures of merit for applications. The proposed miniaturization technique is potentially promising for antenna applications and the results presented in the paper constitute a relevant proof for the usefulness of the metamaterial concepts in antenna miniaturization problems.

Rigorous experimental characterization of several meta material loaded antennas and proof of principle results were provided.

This study aims to characterize a novel glass/epoxy architecture sandwich structure for electronic boards. Understanding the thermo-mechanical behavior of these composites is important because it is possible to pre-determine whether defined “internal” thick laminates will be suitable for embedding components in the direction of the axis “z,” i.e. this method of manufacturing multilayer laminates can be used for incoming miniaturization in electronics.

Laminates with a low glass transition temperature (Tg) and high Tg with E-glass type were treated, tested and compared. Testing samples were manufactured by nonstandard two steps unidirectional lamination as a multilayer structure based on prepreg layers and as “a sandwich structure” to explore its effect on thermo-mechanical properties. The proposed tested method determines the time and temperature-dependent viscoelastic properties of the board by using dynamic mechanical analysis, thermo-mechanical analysis and three-point bend tests.

This testing method was chosen because the main property that promotes sandwich structure is their high stiffness. Glass/epoxy stiff and thermal stabile sandwich structure prepared by nonstandard two-stage lamination is proper for embedding components and the next miniaturization in electronics.

Compared with by-default applied glass-reinforced homogenous laminates, novel architecture sandwich structure is attractive because of a combination of strength, stiffness and all while maintaining the miniaturization requirement and multifunctional application in electronics.

The purpose of this paper is to study and calculate the electrical characteristic of an equilateral triangular microstrip patch antenna that is proposed for dual frequency operation using the pin diode. The electrical characteristic of an equilateral triangular microstrip patch antenna is proposed for dual-frequency operation. Spur lines and ON/OFF condition of the pin diode are utilized to switch the resonant frequency of the patch. The presence of spur lines excites the surface current of the patch which is dependent on the resonant frequency of an equilateral triangular microstrip patch. Insertion of the diode in the spur lines gives a better result and compactness in patch design, which improves the miniaturization in size of patch.

Antenna Design Aspects: A basic structure of an equilateral triangular microstrip antenna (ETMA) having two spur lines and one pin diode positioned in between the spur line is considered in this paper. The design parameters are chosen on the basis of substrate materials having relative permittivity less than three. Specification of the antenna is given in Table I. Substrate material used is RT Duroid 5,880; relative permittivity of the substrate er is 2.2; thickness of dielectric substrate h is 1.5 mm; sides of equilateral triangular patch a are 10 mm, spur width s is 0.5 mm; and spur length b is 2.0 mm.

This paper gives an account of achieving polarization swiftness with coplanar waveguide (CPW) feed. The miniaturized size of the antenna is 35 × 30 mm2. Switchable microstrip equilateral triangular antenna has been demonstrated for dual-frequency operations. The resonant frequency of an ETMA can be adjusted by setting the diode in an ON and OFF state. The design improves the miniaturization in size with a discussion of radiation density. The excited patch surface current is limited to flow around just the mid of the patch in simple ETMA with a single slit cut. It is observed that for an ETMA, when the diode is in the ON state at 9.16 GHz, the excited patch surface current is highly distributed in the patch compared to when the diode is in the ON state at 11 GHz. Similarly, it is observed that the excited surface patch current is highly distributed when the diode is in the OFF state in both frequencies (9 and 11.96 GHz). The mode is changed by the use of a switch at time and it is suitable for wireless communication applications.

Spur lines and the ON/OFF condition of the pin diode are utilized to switch the resonant frequency of the patch. The presence of spur lines excites the surface current of the patch which is dependent on the resonant frequency of an equilateral triangular microstrip patch. Insertion of the diode in spur lines gives a better result and compactness in patch design, which improves the miniaturization in size of the patch.

The purpose of this paper is to develop lightweight actuators in order to replace conventional hydraulic/pneumatic actuators and to apply the actuation system to a small flying vehicle.

A new type of control surface using a piezo‐composite actuator for a small flying vehicle has been designed and manufactured. The piezo‐composite actuator is composed of a piezoelectric ceramic layer, a carbon/epoxy layer and glass/epoxy layers. Through this, the miniaturization and weight reduction of the actuation systems for flying vehicle can be achieved. A simple model of the control surface has been manufactured and evaluated through experiments.

The performance test results showed that the developed actuator can produce stable angle of attack independent of the applied loading. A radio controller for the actuator was developed to control the motions wirelessly. It was found that the piezo‐composite actuator and its integrated controller system have a possibility to be used not only as a small flying vehicle but also as a control surface actuator of a small unmanned flying robot through the miniaturization of power supply and control system.

The paper describes the procedures of designing and manufacturing smart structure application of the piezo‐composite actuator with performance evaluation and comparison method. It is expected that piezo‐composite actuator can be used as a small flying vehicle control surface actuator through the miniaturization of power supply and control system with the use of the integrated radio controller MIPAD.

In the last 10 years there has been an increasing trend towards miniaturisation in mass spectrometry. Miniature versions of magnetic sector, time of flight (TOF) and quadrupole mass spectrometers (QMS) have all been developed. Some of these systems use silicon microengineering technology, e.g. MEMS, to achieve the small geometries necessary, other systems use conventional engineering but on a reduced scale. The scientific advantages of miniaturisation include the ability to measure and monitor at higher vacuum pressures than hitherto (>10⁻² mbar). Miniaturisation also offers advantages due to the reduced cost and resulting portable nature of the smaller instruments.

This paper is aimed to study the design of a miniaturized filter with tri-band characteristics. In this paper, perturbation is used to realize circuit miniaturization and multi-band by exploiting the inductive property. During this process, vias are added for twofold benefit, namely, circuit miniaturization and enhanced frequency selectivity at high frequency. Thus, with the introduction of the shorting via, the single-band dual-mode bandpass filter is converted into a tri-band filter with a smaller electrical size.

This paper presents the design and characterization of a miniaturized two-port filter with tri-band operating characteristics. The proposed filter is constructed using a square patch resonator operating at 5.2 GHz with a capacitively coupled feed configuration. A square perturbation is added to the corner of the square patch to achieve diagonal symmetry and to excite dual mode. The perturbation offers a sharp transmission zero defining bandwidth of the proposed filter. In addition, a shorting post is introduced to achieve an 88% size reduction by lowering the operating frequency to 1.8 GHz.

The prototype filter has insertion less than 1.2 dB and return loss better than 12 dB throughout all the realized frequency bands. The prototype filter is fabricated and the simulation results are validated using experimental measurements. The realized fractional bandwidths of the proposed bandpass filter are 11/5.6/1 at 1.8/4.6/5.85 GHz, respectively. The quality factor of the proposed antenna is greater than 80 and a peak Q-factor of 387 is realized at 5.85 GHz. The high Q-factor indicates low loss and improved selectivity. The rejection levels in the stopband are greater than 20 dB.

The results indicate that the proposed filter is a suitable choice for low-power small-scale wireless systems operating in the microwave bands. The realized filter has the smallest footprint of 0.36λ_eff  × 0.19λ_eff where λ_eff is the effective wavelength calculated at the lowest frequency of operation.

Crack sensor based on RFID tag has become a research hotspot in the field of metal structural health monitoring for its significant benefit of passive wireless transmission. While in practice, crack location will impact the performance of crack depth-sensing tag. The purpose of this paper is to provide a method for reducing disturbance of crack location on crack depth-sensing tag.

The effect analysis of crack location on crack depth-sensing tag is presented first to find disturbance reason and disturbance law. On the basis of that, a miniaturized tag is proposed to improve the current distribution and reduce the disturbance introduced by crack location.

The degree of crack location disturbance is closely related to the current distribution in the coverage area of tag. Because sensing tag performs better when crack locates in the high current density area, miniaturization of sensing tag is exploited to expand the high current density area and make the area more symmetrical. The simulated and experimental results demonstrate that tag miniaturization can enhance the performance of crack depth-sensing tag.

This paper provides a method to enhance the performance of crack depth-sensing tag.