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In this work, a microstrip antenna array that consists of 16 elements is designed at a frequency of 28 GHz, with a dimension of 35 mm × 33.5 mm and an operational bandwidth of 27.7–28.3 GHz. The idea is putting two antenna arrays next to each other on the same substrate and ground plane, as well as minimizing the overall size. This work presents a mutual coupling reduction for two arrays and studies the performance of the antennas through the suppression of surface wave propagation in a given frequency range. It proposed a new configuration for an artificial magnetic conductor (AMC) created by microstrip technology placed at a closed distance (0.3λ0) between the two antenna arrays. The improvement in the isolation between the two adjacent antenna arrays was studied according to the H-plane with a periodic unit cell of the AMC. The mutual coupling reduces to −40.0 dB at the operation frequency and isolation of 17 dB. The antenna array is also characterized by a good envelope correlation coefficient (ECC). The CST Microwave Studio electromagnetic solver was used to design, improve, and miniaturize the proposed configuration.

This chapiter starts with a general definition of the antennas. The next parts will talk about a microstrip antenna from the side of the double band in order to get an antenna that can do both reception and emission as well as developing the azimuth and angular resolution. This chapter has also introduced an antenna that separates the feeding part from the rayonnant one in an effective way that can enable us to develop the abilities of the radar antenna. Besides, it would also cope with the mechanic relation of the antenna. Another work has been presented to make electronic scanning more effective and faster. This would allow us to get rid of mechanic circulation by using butler matrix. Developing the antenna from the angular resolution has also been presented through widening the bandwidth by DGS technique and widening the reach via using the antenna array. Among the biggest problems are the surface waves and mutual coupling that present significant challenges to the designer because of their graduation of the antenna performance especially in the radar system.

This chapter provides a survey on radio frequency identification technology (RFID), especially passive RFID technology, which is recommended and highly used in the industrial environment due to its advantages such as low cost of manufacturing and high read range. The chapter reviews the historic of RFID technology, including frequency bands allowed, mode of communications, and different types of RFID TAGs. Then, there is a description of the methodology of passive RFID TAG design and methods used to match input impedance and miniaturization. At the end, a new contribution in passive RFID TAGs design is presented using miniaturization methods such as integration of split ring resonator theory and meander technique.

Radio frequency identification is being overloaded with data information, making wideband band antennas very appealing. In this paper, we present a new design of dual band antenna for RFID reader applications operating at 2.45Gz and 5.8GHz with an average gain of 1.16dB at the lower frequency band and 3.2dB at the higher frequency band. The antenna is designed on an FR-4 substrate having a relative dielectric constant of 4.4 and loss tangent of 0.025. The proposed antenna is simulated, designed and, optimized using CST Microwave Studio and has a small size of 32 mm x 26 mm x 1.6 mm. The antenna consists of a steeped rectangular patch antenna using a partial ground plane loaded a modified split ring resonator. The metamaterial structure was designed and optimized to operate at 2.45GHz and its effective parameters was verified using the Nicolson-Ross Weir method. The performance of the proposed antenna is confirmed by another 3D electromagnetic solver HFSS.

The development of miniature antennas for bio-medical applications has attracted the attention of many researchers in the last years. In this letter, we provide a miniature antenna for the RFID tag for identifying patients in African and European hospitals. The proposed antenna is designed on a flexible silicon substrate with a relative dielectric constant of 11.9 and a thickness of 1.6mm. An in-depth study of the proposed wearable antenna was made in free space and on human tissue. The achieved results showed good performance in terms of miniaturization, bandwidth, impedance matching and, reading distance. The presented tag antenna is designed and simulated by using CST-MWS solver and the results were validated by HFSS and both results are in good agreement.

This paper presents a novel approach to design a compact miniature coplanar band-pass filter by using rectangular split ring resonator. This proposed circuit is designed for the Industrial, Scientific and, Medical (ISM) frequency band applications at 2.4 GHz. At the first stage, a metamaterial resonator is designed and simulated in a TEM waveguide to verifiy its electromagnetic proprieties around the desired frequency bands. At the second stage, a band pass filter is designed using the proposed metamaterial resonator. Many parametric studies are realized to investigate the effect and influence of some resonator parameters on the proposed BPF performances. ADS Agilent and CST-MWS solvers are used in order to verify the simulated results. The circuit frequency responses show an excellent insertion loss and good return loss in the passband.

This study presents the optimum design of a $4\times 4$ planar Butler matrix array as a central feature of a switched beam smart antenna system operating at 28 GHz for Ka-band applications. The design is developed on a multilayer structure and the antenna arrays are feeding by using slots. In this work the slot optimized and defined on the ground plane to achieve an optimum feeding, with RO3003 substrate of dielectric constant equal to 3 and loss tangent equal to 0.001. In the 4x4 Butler matrix, four input ports are used to feed four networks composed of four microstrip patch antennas creating the beamforming array. Such network can produce four uniform orthogonal beams, at 12°, −12°, 28° and −28°. Design details and simulation results for the components (hybrid coupler, crossover, phase shifter) used to implement the matrix are provided by using two electromagnetic solvers one based on Moements method and the second one on Finite Integration Technique (FIT).

In this work, we present a novel miniature band stop filter based on double negative metamaterial, this circuit is designed on a low-cost substrate FR-4 of relative permittivity 4.4 and low tangential losses 0.002. The proposed filter has a compact and miniature size of 15 mm in length and 12mm in width without the 50 Ω feed lines. The resonator was studied and analyzed with a view to achieving a band-stop behavior around its resonant frequency. The band-stop characteristics are obtained by implementing the metamaterial resonator on the final structure. The obtained results show that this microstrip filter achieves fractional bandwidth of 40% at 2 GHz. Furthermore, excellent transmission quality and good attenuation are achieved. This filter is an adequate solution for global system for mobile communications (GSM).

In this paper, a novel compact broadband with high-rejection lowpass filter (LPF) based on one resonator of omega topology is presented. The effect of cascaded cells on the filter performance is examined, which allows high selectivity and harmonic suppression in the rejection band. Using two shaped omega resonators LPF Structure, a new miniature bandpass filter (BPF) is designed and simulated using a sample transformation based on J-inverter method by introduce a gap in the middle of the signal line. The proposed LPF presents the advantages of selectivity, compactness, low insertion loss, broad pass band and wide rejected band from 15.95 GHz to 25 GHz, and transmission zero allows -32 dB around 21 GHz. A basic compact LPF with two shaped omega resonators is developed to provide a high compactness, selectivity and the ability of reconfiguration to BPF. Such LPF structure with all these potential features could be a good candidate for the most applications in integrated RF and microwave circuits.

The paper proposes a four-circular elements microstrip patch array antenna with Defected Ground Structure (DGS). The antenna array designed and simulated by three steps, started by a single element design using inset feeding technique, the array antenna was combined using a T-junction power divider, and a Microstrip Curved Bend power divider was constructed. Simulations predict a good matching impedance at 30 GHz with a return loss of -40 dB. Two dumbbells shaped defected ground structure have been integrated below the transmission line, which will allow to adjust transmission line inductance and capacitance in order to increase bandwidth up to 3.1 GHz, without significant effects on radiation pattern. A prototype of the antenna was designed on an FR-4 substrate with a dielectric constant ( ) of 4.3 and loss tangent (tanδ) of 0.025 with thickness of 0.465 mm. The array antenna is designed and simulation using two electromagnetic solvers.

In this paper, an RFID tag based on a Square Split Ring Resonator (SQUARE SRR) is studied and validated for RFID application in UHF band [867-869MHz].In RFID applications, the reading distance and miniaturization of the tag size are very important. Hence, those requirements encourage RFID designers to use SRR, which offers a small size and easy to be matched in term of response at suitable frequency. The proposed RFID tag is mounted on an FR-4 epoxy substrate with a dielectric relative permittivity e r =4.4 and thickness of 0.8mm.It is a double metallic structure based on a modified SQUARE SRR interconnected with a microchip "ALIEN H3" and a Defected Ground Structure (DGS). The results of simulation show a return loss of -26.57dB at 868MHz and a read range around 1 m. The RFID tag is miniature and has small size around 31 × 31 mm2.

In this paper, a broadband microstrip antenna array matched with quarter wave microstrip line matching and Defected Ground Structure technical is proposed. The purpose of this paper is to use Defected Ground Structure (DGS) in microstrip antenna array to achieve an antenna array for ka-band application. The DGS position which is under the quarter wave line matching has an effect that has been presented in this paper. This work started with the single element antenna matched to a band [28–31.5] Ghz. After That, we have constructed and designed the antenna array in order to increase the gain and to obtain a radar antenna with high performances. The antenna array structure, fed by microstrip line and matched by quarter wave transformer, is printed on a Duroid 5880 substrate with dielectric constant of \(\epsilon _r\) = 2.22 and, tangent value 0.004 and 0.4 mm thickness. The simulations of this study are performed on CST Microwave Studio.

Wireless microwave power transmission (WPT) has become a new alternative technology to solve global energy problems, including the depletion of fossil fuel sources. This paper is part of the use of renewable energies such as WPT to power the various sensor networks that surround our environment. In this manuscript, an efficient 2.45 GHz Rectenna system have been designed, optimized and simulated for applications involving remote power supply. As a first step, a 2.45 GHz miniature microstrip antenna have been designed using Defected Ground Structure technology in order to switch the frequency from 5.8 GHz to 2.45 GHz with a gained size reduction reaching 70%. In the other side, a high output voltage 2.45 GHz Rectifier structure using voltage doubler topology have been developed for low power levels. The Rectenna have been simulated using Advanced Design System and CST Microwave Software and we have employed FR4 substrate with dielectric permittivity constant 4.4, thickness of 1.6 mm and loss tangent of 0.025. We have obtained satisfying results in terms of conversion efficiency and output voltage reaching 15 V.

The differential phase shifter is an interesting four-port passive microwave network composed of two separate lines, the main line and the reference line, and providing stable phase difference between the two output signals over the specified bandwidth of interest. The most common differential phase shifter is the coupled-line Schiffman phase shifter. In this paper, a novel 90 degrees differential microstrip phase shifter configuration employing a half wavelength transmission line loaded with three open stubs is presented, the proposed design could achieve excellent performance with low phase variation over a wide bandwidth compared to the standard Schiffman phase shifter. The simulated results accomplished with the use of CST Microwave Studio and advanced design system (ADS), were found to be in good agreement and have shown that the proposed loaded-stub phase shifter achieved less than 1.1 dB insertion loss, greater than 13 dB return loss and constant 90±5 degrees phase shift over an 89 percent bandwidth

This contribution introduces a novel broadband power amplifier design, operating in the frequency band ranging from 1.5 GHz to 3 GHz which cover the mainstream applications running in L and S bands. Both matching and biasing networks are synthesized by using microstrip transmission lines. In order to provide a wide bandwidth, two broadband matching techniques are deployed for this purpose, the first technique is an approximate transformation of a previously designed lumped elements matching networks into microstrip matching circuits, and the second technique is a binomial multi-sections quarter wave impedance transformer. The proposed work is based on ATF-13786 active device. The simulation results depict a maximum power gain of 16.40 dB with an excellent input and output matching across 1.5 GHz ~ 3 GHz. At 2.2 GHz, the introduced BPA achieves a saturated output power of 16.26 dBm with a PAE of 21.74%, and a 1-dB compression point of 4.5 dBm input power level. The whole circuitry is unconditionally stable over the overall bandwidth. By considering the broadband matching, the proposed design compares positively with the most recently published BPA.

In this article, we propose a novel design of large rejected band of miniaturized ultra wide band (UWB) of a planar CPW low pass filter “LPF” based on the use of periodic elements of ‘e’ slots. The goal of this work is to develop a new structure of Low Pass Filter with the following criterion: Miniature, Compact and Easy for Fabrication. The Miniaturization of this structure is achieved by entering the 'e' slot in etching area in the ground of CPW line, to save the standard gap of the adapted coplanar line. The designed coplanar LPF is a compact filter having a large band pass and extended stop band, with the possibility to associate easily with others RF and microwave planar circuits. The entire area of the proposed structure of CPW LPF is 14.3x20 mm2.

This chapter introduces an overview of coplanar technology and the general techniques and process to improve the response and characteristics of microwave components. A new circular defected ground structure (DGS) with shaped coplanar line is investigated for compact stopband filter (SBF) for microwave and millimeter wave applications. With this structure, the response of resonant element in 20 GHz exhibits the bandstop function. The proposed DGS is also modified by introducing four symmetrical slots with L-configuration in conductor line of a coplanar circuit to improve separately the stopband and passband performances. An equivalent circuit model derived for the proposed structures will be provided.