Microstrip Antennas and Arrays

Abstrak—Jaringan Wireless Fidelity (Wi-Fi) beroperasi pada frekuensi 2,4 GHz dan menggunakan gelombang
radio untuk pemancaran dan penerimaan data sinyal sehingga diperlukan antena sebagai transciever gelombang
tersebut. Antena Mikrostrip adalah jenis antena yang sedang berkembang dan banyak digunakan untuk perangkat
telekomunikasi modern yang salah satunya adalah aplikasi berbasis Wi-Fi 2,4 GHz. Antena mikrostrip yang dirancang
pada penelitian ini adalah 4 elemen patch persegi panjang dengan teknik peripheral slits  disusun secara linear array
2x2 dan beroperasi pada frekuensi 2,4 GHz sampai 2,5 GHz. Teknik pencatuan yang digunakan pada perancangan
antena adalah saluran microstrip. Hasil rancangan susunan empat elemen array peripheral slits ternyata dapat
mengurangi ukuran dimensi antena sampai sebesar 17% dibandingkan dengan empat elemen tanpa peripheral slits.
Hasil simulasi bandwidth yang didapatkan pada empat elemen peripheral slits sebesar 320 MHz (2,253 GHz–2,573
GHz) dengan persentase bandwidth sebesar 13,07%. Hasil simulasi pada frekuensi tengah 2,448 GHz menghasilkan
nilai return loss sebesar -26,14 dB dengan VSWR 1,104. Hasil pengukuran susunan empat elemen peripheral slits
didapatkan bandwidth sebesar 150 MHz (2,424 GHz–2,574 GHz) dengan persentase bandwidth sebesar 6,12%.
Hasil pengukuran pada frekuensi tengah 2,448 GHz didapatkan return loss sebesar -16,88 dB dengan VSWR 1,304.

A MIMO antenna array has been presented in this paper, which has four rectangular microstrip patches as an antenna element(s). An elliptical slot is etched on every radiating patch. The antenna array is simulated in HFSS yielding resonating frequencies of 2.42, 3.49 and 4.98 GHz at S11 <; -10 dB making it applicable for WLANs. RT Duroid 5880 has been used as substrate. The gain ranges from 7 to 11 dB at all resonant frequencies with narrow bandwidth, improving interference rejection characteristics of the proposed antenna. Complete design procedure, comprehensive analysis of mutual coupling among the patches and radiation patterns are also discussed.

Narrow bandwidth and high loss performance limits the use of reflectarray antennas in some applications. This article reports on the feasibility of employing strategic reflectarray resonant elements to characterize the reflectivity performance of reflectarrays  in X-band frequency range. Strategic reflectarray resonant elements incorporating variable substrate thicknesses ranging from 0.016λ to 0.052λ have been analyzed in terms of reflection loss and reflection phase performance. The effect of substrate thickness has been validated by using waveguide scattering parameter technique. It has been demonstrated that as the substrate thickness is increased from 0.508mm to 1.57mm the measured reflection loss of dipole element decreased from 5.66dB to 3.70dB with increment in 10% bandwidth of 39MHz to 64MHz. Similarly the measured reflection loss of triangular loop element is decreased from 20.25dB to 7.02dB with an increment in 10% bandwidth of 12MHz to 23MHz. The results also show a significant decrease in the slope of reflection phase curve as well. A Figure of Merit (FoM) has also been defined for the comparison of static phase range of resonant elements under consideration. Moreover, a novel numerical model based on analytical equations has been established incorporating the material properties of dielectric substrate and electrical properties of different reflectarray resonant elements to obtain the progressive phase distribution for each individual reflectarray resonant element.

A miniaturized ultra wideband (UWB) planar array antennas for C-band aircraft weather RADAR applications is presented. Firstly, the effect of the ground plane is studied. Later, the realization and experimental validation of the geometry that has an UWB characteristic are discussed. This array antennas is composed of a twenty-four radiating element that is etched onto FR-4 substrate with an overall size of 162 × 100 × 1 58 mm 3 and a dielectric constant of ε r = 4 4. The results show that this miniaturized array antennas gives us a bandwidth which is about 115% and a gain greater than 13 dB which are required in aircraft weather radar applications.

In this paper, several designs of micorstip arrays antennas, suitable for wireless communication applications, are presented. This paper demonstratesseveral shapesof microstrip array antennas, such as rectangular and circular patch antennas array. Specifically, 4x1, 2x1, and single element of both shapes are designed and simulated bya full wave simulator(IE3d). Moreover, this paper presents acomparison between both rectangular and circular antenna arrays.Since, the resonance frequency of these antennas is 2.4 GHz, these antennas are suitable for ISM band and WLAN.

This paper presents the design, simulation, and implementation of band pass filters in rectangular waveguides with radius, having 0.1dB pass band ripple and 6.3% ripple at the center frequency of 14.2 GHz. A Mician microwave wizard software based on the Mode Matching Method (MMM) was used to simulate the structure of the filter. Simulation and measured results show the validity of the waveguide band pass filter design method.

Automobiles connectivity to each other and with other infrastructure (e.g. power grid, base stations etc.) are becoming more popular. The advancement in autonomous vehicle and Internet of Things (IoTs) gives the challenge to incorporate high efficiency antennas into the vehicle for wireless communication. However, the transmitters and receivers need to be low-profile, high bandwidth, high gain, and cost effective to enable vehicle telematics. In this paper, a dual band low profile shark fin integrated multi-input multi-output (MIMO) antenna is proposed for 5G and Wi-Max communications. Initially, a corporate fed patch antenna array and a quasi-Yagi antenna is designed for 5G and Wi-Max frequency bands respectively. These two optimized antennas are vertically incorporated, and further optimized to work for dual band applications at 26 GHz and 5.5 GHz. The effects of the gap and parasitic elements between the antennas on the resonance and realized gain pattern are parametrically studied. The simulation results show that the dual band antenna operates from 5.16 GHz to 6.05 GHz and 25.625 GHz to 26.36 GHz with 10 dB return loss bandwidth with a realized gain of 4.43 dB at 5.5 GHz and 4.79 dB at 26 GHz. The scattering parameters, realized gain, and 3D radiation pattern are presented in the results section. Index Terms-Vehicle antenna, dual band, 5G, antenna array, Yagi-Uda antenna, Wi-Max, shark fin antenna.

The microstrip patch antenna in rectangular shape and inset feed line is designed. It is analysed using IE3D software. The size of proposed antenna is 49.41mm X 41.36mm. The antenna is designed for 2.4 GHz frequency for ISM band. This frequency band is very useful for industrial, scientific and medical applications.  The antenna parameters like return loss, smith chart, VSWR, radiation pattern of designed antenna are reported.

The Indian regional navigational satellite system
(IRNSS) is an autonomous regional satellite navigation system
being developed by the Indian Space Research Organization
(ISRO) which would be under complete control of the Indian
Government. The requirement of such a navigation system is
driven by the fact that access to Global Navigation Satellite
System, GPS is not guaranteed in hostile situations. Design of
IRNSS antenna at user segment is mandatory. The simulated
Microstrip patch antenna operates on the frequency of L5 band
(1176.45 MHz) which is used for positioning services. Its
parameters are enhanced by making 2x8 array with Teflon
substrate, increasing gain, directivity, and efficiency to 17.3dB,
18.1dBi and 95.58% respectively. For fabrication purpose
substrate FR4 substrate can be used for which 10.1dB gain and
15.4dBi directivity is obtained till 2x8 array. Results of
simulation are compared with hardware results using Vector
network analyzer for two models of all array.

—Global Positioning System (GPS) jammers add excessive noise to the received low power GPS signals and have capability to either weaken or completely destroy the positioning performance of GPS receivers for both civilian and military users. Researchers are actively working to develop GPS receiver systems resistant to interference sources. Our aim is to develop a system based on spatial filtering of jamming signals through the use of an active antenna array which is capable to control its radiation pattern by utilizing signal processing techniques. Array radiation pattern is controlled to maximize gain in satellite directions and to create null regions toward jammers. Adaptive beamforming methods provide necessary weighting coefficients to form desired radiation patterns using received data. In this paper, design, production and tests of an active antenna array is presented with implementation of adaptive beamforming algorithms using commercially available development boards.

This paper proposes a design of 0.15μm Monolithic Microwave Integrated Circuit (MMIC) power amplifier using GaAs pHEMT technology at 2.4 GHz which employs feed forward linearization technique to improve linearity. The amplifier is designed to operate in personal communication systems (PCS) frequency range using WIN semiconductor GaAs pHEMT technology. Single stage power amplifier is designed in lumped and distributed components with its layout. Linearity of PA is improved by Feed forward Linearization technique. To evaluate the performance of proposed linearized amplifier, Advanced Design system (ADS) tool is used. The designed circuit results with 13.65dBm output power at 1dB compression point (P1dB), 6dB power gain and maximum Power added efficiency of 16.4%. Linearity achieved by feed forward linearizer circuit with third order intermodulation suppression of 30dBc for the output power level of 8.217dBm and 1dB compression point at an input power of 15 dBm whereas 6 dBm for the Power amplifier without feed forward linearizer circuit. The designed Power amplifier system with feed forward linearizer had IMD3 suppression of 30dBc which is in appreciable range with improvement in 1dB compression point.

International Journal of Microwave Engineering (JMICRO) is a peer-reviewed, open access journal which invites high quality manuscripts that focuses on Engineering and theory associated with microwave / millimeter-wave technology, guided wave structures, electromagnetic theory and implementation. Authors are invited to submit original research works that stimulate the development of latest technology in industry and academia. Good quality review papers and short communications are also acceptable. Research areas suitable for publication include, but are not limited to the following fields:

A compact, circular UWB fractal antenna with triple reconfigurable notch rejection bands is proposed. It rejects the crowded frequency bands WiMAX, WLAN and X band interferences produced in UWB communication systems. The proposed fractal structure consists of a basic circular patch with circular fractal iterations. By employing this new structure of fractals, the overall size of antenna is reduced 53% to 21x25 mm, in comparison with traditional circular monopole antenna. The implemented antenna operates at 3.1-10 GHz. Re-configurability is realized by designing slots and split ring resonators in desired frequencies with the attached PIN diodes. WLAN band rejection was realized by creating a pair of optimized L-shaped slots in the ground plane. By etching a split ring resonator and a U-shaped slot, X and WiMAX bands were also rejected. Furthermore, by attaching diodes to aforementioned slots and designating the diodes on/off, different bands can be included or rejected. In time domain, the antenna properties are evaluated by a figure of merit called fidelity factor. Finally, the antenna properties are measured in anechoic chamber and the results agrees with simulation findings.

The purpose of this paper is to design a rectangular patch microstrip antenna using tapered line Transfer coupled feed with  complete mathematical calculations and  the results are simulated using IE3D software with an operating frequency of 5 GHz. It is a low profile patch antenna for wireless application. If we design the same antenna using Transfer coupled without tapering the line then return losses is very high and after tapering of line the return losses of the antenna has been decreases. Microstrip patch antennas are widely used because they are compact in size, light in weight and easy to integrate on any device. The performance measures of antenna return loss, voltage standing wave ratio, radiation pattern is calculated which shows that the antenna performance was good and results  were optimum.

International Journal of Antennas is a peer-reviewed, open access journal that publishes original research as well as review articles in the field of antennas and its allied domain. This journal aims to bring together leading academic scientists, researchers, engineers and research scholars to exchange and share their experiences and research results in their specialized arena in antenna engineering. The journal invites good quality research and review papers for publications.

Proper narrowband antenna design for wearable devices in the biomedical application is a significant field of research interest. In this work, defected ground structure-based microstrip patch antenna has been proposed that can work for narrowband applications. The proposed antenna works exactly for a single channel of ISM band. The resonant frequency of the antenna is 2.45 GHz with a return loss of around-30 dB. The-10dB impedance bandwidth of the antenna is 20 MHz (2.442-2.462 GHz), which is the bandwidth of channel 9 in ISM band. The antenna has achieved a high gain of 7.04 dBi with an increase of 17.63% antenna efficiency in terms of realized gain by using defected ground structure. Three linear vector arrays of arrangement 1x 2, 1x 4 and 1x 8 have been designed to validate the proposed antenna performances as an array. The proposed antenna is light weighted, low cost, easy to fabricate and with better performances that makes it suitable for biomedical WLAN applications.

In order to improve return loss, compactness and efficiency of antenna defected ground structure has been used. The performance of antenna is characterized by the shape, dimension and location of defected structure at specific position of ground. This paper presents defected ground structure (DGS) implemented with rectangular strip in the ground plane. The design with DGS has been analyzed taking different dimensions of rectangular Slot and achieve optimized dimensions with the help of HFSS(High Frequency structural simulator).

Ground station antennas are a part of TTC system, generally, Yagi-Udi antennas and Parabola dish antenna are using in Earth segment to communication with LEO small satellites, this paper uniquely presents the three huge antennas of Beihang University ground station which are communicating with some microsatellites with view window above Beijing, China. The ground station contains two Yagi-Udi antennas for VHF/UHF and an S-band dish antenna for reception of payloads data. For verification feasibility of the antennas, simulations have been accomplished according to the antennas requirements. Eventually, the simulations assisted to recognize the matched commercial ground station antennas based on comparison of the simulations with commercial antennas and the matched ones are chosen for the implementation of Beihang University ground station antennas.

Microstrip patch antennas are the most useful antennas for the present trend of applications in communications. The well known advantageous mechanical characteristics (low profile, light weight, planar but conformal to non-planar structures, easy to fabricate), flexibility in terms of electromagnetic parameters (radiation pattern, gain, impedance, polarization) and low cost are the key features of the success of such antennas. To meet the requirements of aircraft, spacecraft, satellite and missile applications where size, weight, cost, performance, ease of installation, low profile and easy integration to circuits, high efficiency antennas are required. Microstrip antenna arrays are most suitable for such applications. In this paper various circular patch antenna arrays are designed for the application of WLAN (wireless local area network) at 2.4GHz. Single patch antenna is designed using probe feeding technique. Arrays of 2x1 and 4x1 are also designed using edge feeding technique. The antenna arrays are designed and simulated on FR4 substrate and excited using probe and edge feeding techniques. The antenna arrays are simulated using the High Frequency Structure Simulator (HFSS) software version v17.2 and the parameters like gain, return loss, radiation pattern and VSWR are evaluated at that frequency.

Antena mikrostrip dapat menjadi salah satu pilihan utama dalam perkembangan teknologi berbasis wireless. Antena jenis ini memiliki ukuran yang kecil, ringan dan mudah diintegrasikan dengan rangkain. Pada penelitian ini dibuat simulasi dan realisasi antena mikrostrip dengan optimasi menggunakan algoritma Simulated Annealing yang bekerja pada frekuensi 2,4 GHz. Algoritma simulated annealing digunakan untuk mengoptimasi dimensi patch antena dilihat dari sisi return loss. Untuk parameter yang lain seperti panjang dan lebar feedline, tebal substrat telah ditentukan berdasarkan perhitungan awal antena mikrostrip. Optimasi ini dilakukan menggunakan Matlab dan disimulasikan menggunakan CST Microwave Studio 2014 yang kemudian direalisasikan ke dalam bentuk fisik. Bentuk antena mikrostrip yang dibuat adalah belah ketupat, hasil optimasi menunjukkan bahwa dengan mengubah dimensi patch yang dioptimasi dan disimulasikan menggunakan CST, antena ini dapat memenuhi kriteria antena yang baik yaitu memiliki nilai return loss <-10 dB dan VSWR < 2 dengan dimensi patch yang dibangkitkan secara acak berdasarkan perubahan parameter dari cooling schedule pada Simulated Annealing. Cooling schedule yang paling sesuai dengan simulasi adalah pada tipe quadratic. Optimasi yang dilakukan dan simulasi pada CST Microwave Studio 2014 telah sesuai seperti yang diharapkan yaitu memiliki return loss-31,023613 dB, VSWR 1,0578404 , frekuensi kerjanya berada pada 2,4 GHz dan bandwidth 644 MHz. Hasil pengukuran berdasarkan antena yang telah direalisasikan menggunakan algoritma Simulated Annealing terdapat pergeseran frekuensi yaitu ada pada 2,447 dengan return loss-27,03 dB, VSWR 1,07 serta bandwidth 620 MHz. Kata Kunci : antena, mikrostrip, cooling schedule, simulated annealing, return loss, bandwidth, VSWR, gain, pola radiasi, polarisasi I. PENDAHULUAN Teknologi komunikasi nirkabel yang saat ini berkembang pesat dalam dunia telekomunikasi menjadikan perkembangan antena juga semakin bertambah. Sebagai salah satu bagian yang menjadi ciri khas dalam sistem komunikasi nirkabel, antena diperlukan baik bagi perangkat yang menerima sinyal maupun perangkat yang memancarkan sinyal sehingga sinyal radio dapat tersalurkan ke udara. Perkembangan antena saat ini tidak hanya digunakan untuk komunikasi audio atau suara saja namun telah terintegrasi dengan komunikasi data sehingga membutuhkan perangkat yang dapat menghubungkan komunikasi antara perangkat komunikasi satu dengan yang lain [1]. Antena mikrostrip dapat menjadi pilihan utama untuk merealisasikan pengembangan teknologi telekomunikasi berbasis wireless ini, karena antena mikrostrip memiliki kelebihan yang ringan dan mudah diintegerasikan dengan rangkaian. Perangkat antena dibedakan berdasarkan bentuk dan kualitas bahan yang digunakan, sehingga kemampuan tiap-tiap antena untuk memancarkan maupun menerima suatu gelombang elektromagnetik tentu berbeda. Tentu saja antena mikrostrip juga memiliki beberapa kekurangan yang salah satunya adalah cara mengoptimasinya yang masih manual sehingga tidak efisien. Untuk mengatasi hal tersebut maka optimasi dilakukan secara otomatis menggunakan

A compact printed antenna is described that exhibits adequate transient performance for ultrawideband (UWB) applications and it is further adequate for polarization diversity schemes. The antenna is based on an original combination of two crossed exponentially tapered slots plus a star-shaped slot to produce a stable radiation pattern with very stable polarization over the 3.1–10.6 GHz FCC assigned band. Results are confirmed with measurements. Figures of merit like output pulse fidelity and time window containing 90% of the transmitted energy are analyzed over the entire solid angle and showed to remain quite stable, in line with envisaged UWB system requirements. Compact dual-antenna arrangements are also analyzed in view of potential use for UWB multiple-input–multiple-output implementations.

Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna.

The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

Keywords —ADS (Advanced Design System) Software, KU Band Antenna Array, Schiffman Phase Shifters, Beam Switching Antenna, Varactor Diode (MA46H120).

A broadband, high gain, and dual-polarized singlefed antipodal Fermi tapered slot antenna (AFTSA) with a sine shaped corrugation is presented. The proposed design is employed to realize 1x4 antenna array covering the frequency band from 55 GHz to 65 GHz. The array design achieves a 22.3 dB gain at 60 GHz with a total radiation efficiency of about 90%. The polarization diversity of this antenna makes it suitable for millimeter wave wireless communications, and imaging applications.

In this paper, a new low-Specific Absorption Rate (SAR) antenna is proposed for the sake of safe communication in all situations. The proposed antenna involves a Microstrip patch antenna and a metallic casing loop which leads to SAR reduction. The structure operates at 0.9 GHz and 2.4 GHz which produces 0.52 W/kg and 0.25 W/kg SAR value on the human head, respectively. Then, in order to guarantee the antenna safety feature, the experiments are carried out when the human wear an earring. The impact of metallic earrings in different sizes on SAR distribution is investigated. Also, the antenna orientation and rotation effect is considered in detail. It is concluded that the change of Antenna position or use of metallic earrings makes an extremely significant impact on SAR value. But, the results of the presented antenna demonstrate that the produced SAR value in all positions, do not exceed the safe rate. It makes the antenna a suitable candidate for employing in most tel-ecommunication applications.

In this paper, we present a new inspired metamaterial rectenna which is designed in the microstrip line structure at 5.8 GHz for the wireless transmission of microwave power. The proposed rectenna achieves RF-to-DC conversion efficiency of 52% and a DC voltage of 0.8 V when the received RF power is 1 mW at 5.8 GHz. The feasibility of this concept is presented through full-wave simulations. These simulations results will be updated at the conference with measurement results.

In this paper, we describe about micro strip
patch and slot antenna as well as we also describe
about the reconfigurable antenna and their types like
frequency, polarization, radiation pattern and gain.
Reconfigurable antenna can be achieved by switching
element like MEMES, VARACTOR DIODES, and PIN
DIODES. From all this frequency-reconfigurable
antennas is use because of their high reliability to be
applied in multiple applications using a single antenna,
which cans achieve different frequency. For this, we
use different technique like FRSPMA, RDGS and U- slot.

Transmit arrays have been mostly used for beam collimation applications, either with fixed or scanning beam capability. But transmit arrays can also be used to synthesize power radiation patterns complying with power pattern templates. A new analytical formulation is presented here to obtain a phase-only correction function corresponding to a given power template. The transmit-array transforms the known power radiation pattern of the primary source into a desired output power pattern. The proposed formulation, specialized for axial-symmetric structures, is based on geometrical optics and provides the solution directly from the evaluation of two closed-form first-order differential equations. As a proof of concept, a sec 2 with a roll-off at 45° is defined as the target power pattern, at the 30 GHz Ka-band. A 10.8 dBi radiation pattern with the circular polarization is used to illuminate a 180 mm × 180 mm transmit array with 60 mm focal distance. Previously designed 3.35 mm thick phase-delay unit cells are used as an example to implement the calculated phase distribution over the transmit-array aperture. The measured antenna radiation pattern matches quite well the template, with a steep fall of the radiation at the roll-off angle and low cross-polarization. This validates the concept, the formulation, and the fabricated prototype. Index Terms— Geometrical optics (GO), millimeter-wave antennas, planar lens antennas, radiation pattern shaping, secant squared power pattern, transmit arrays.

— This paper presents a selective frequency reconfigurable antenna, suitable for cognitive radio applications. Reconfigurability is achieved by inserting PIN diode switches in DMS(defected microstrip structure) 'T' slot filter. The proposed antenna is capable of switching between a wide operating band of 3.0 GHz – 10 GHz and six different narrow band operating from 5 GHz to 10 GHz. UWB case is used for sensing the entire band and then adjusting its bandwidth to select the suitable sub-band and pre-filter out the other ones to communicate with wireless devices without interference with others. The proposed antenna patch is a combination of two semi-circular patches. For each case reflection coefficient is calculated, it maintains less than-10 dB throughout the operating frequency. Radiation Patterns for each case also reveal a very low distortion as required. Gain is more than 70% in each case. Index Terms— Cognitive radio, frequency-reconfigurable antenna,P-in diode switches, wideband-to-sub-bands reconfiguration, defected microstrip structure.

A compact PIFA (Planar Inverted F Antenna) for wireless, mobile and automotive applications was designed with full wave simulation software. Size reduction of the antenna was  achieved through an increase in the path length of the currents for a fixed frequency. Finally, a comparison was
made between a non-compact PIFA with a compacted PIFA.
The development of wireless technologies and mobile communications has included considerable research on the production of small, easily adaptable, low cost antennas. One such device, the PIFA (Planar Inverted F Antenna), is widely used in mobile, automotive and wireless communications.
The advantage of using this type of antenna in wireless communications is its small size, low profile, and avoidance of additional matching networks. Thanks to its compact design, the PIFA has recently been developed for multiband applications. For the model investigated, shown in Figure 1, there were two main objectives: one that uses two electromagnetic paths to generate two separate resonant modes; the other offers the two first resonant frequencies of a single electromagnetic path. In the first a slot of variable
shape (L or U, in the figure) or two inductive or capacitive resonators is employed. In the second we add just the resonance frequencies of the first two modes in a manner such that their relationship is about 2. In this case appropriately dimensioned gaps are implemented.

Özet: Küresel Konumlandırma Sistemi'ne yönelik karıştırıcılar, uydulardan gelen düşük güçteki sinyallerin üzerine yüksek güçte gürültü yayını ilave ederek konumlandırma sisteminin kabiliyetini ya kısmen zayıflatır, ya da tamamen devre dışı bırakır. Anten dizilerinin kullanımı, antenin kazanç diyagramında sıfır kazanç bölgeleri oluşturur ve bu sıfır kazanç bölgelerinin dizi sinyal işleme yöntemleri kullanılarak karıştırıcı sinyallerin geliş açılarına yönlendirilmesine olanak sağlar. Bu makale ile, Küresel Konumlandırma Sistemlerine yönelen karıştırıcı tehditlerin uzaysal filtreleme ile bastırılması amacı ile kullanılabilecek 4 elemanlı aktif anten dizisi tasarım çalışmaları; teori, simülasyon, üretim ve ölçüm aşamaları ile incelenecektir. Abstract: Global Positioning System (GPS) jammers add excessive noise to the received low power GPS signals and have capability to either weaken or completely destroy the positioning performance of GPS receivers. Usage of antenna array creates null regions in radiation pattern and make possible to steer these null regions toward jammer sources by array signal processing approaches. In this paper, design of four element active GPS antenna array is examined with subsections of theory, simulation, production and test stages. 1 GİRİŞ GPS, Dünya yüzeyinden 20000 km yükseklikte bulunan uyduların yayınları üzerinden hizmet veren bir navigasyon sistemidir. Navigasyon bilgisi ise en az dört uydudan gelen sinyallerin geliş zamanları kullanılarak çıkarılır. GPS uyduları ile dünya arasındaki mesafeden ötürü GPS sinyalleri alıcılara çok düşük güçlerde ulaştığından, istemli veya istemsiz karıştırıcılar pozisyonlama servisini ya kısmen zayıflatır ya da tamamen devre dışı bırakır. Karıştırıcı tehditlerine karşı tedbir olarak çok sistemli çok frekanslı alıcılar, çentik filtre uygulamaları ve anten dizisi destekli alıcı koruma sistemleri üzerinde çeşitli çalışmalar yapılmaktadır [1]. Anten dizisi destekli alıcı koruma sistemleri, alınan sinyal üzerinde herhangi bir bilgi kaybına sebep olmadığından ve çoğu durumda diğer navigasyon sistemlerine geçiş ihtiyacı da bırakmadığından son dönemlerde popüler olarak üzerinde çalışılan bir konudur. Normal GPS antenleri gökyüzünde olabildiğince fazla uydu alabilmek için yarı uzayda neredeyse yönsüz ışıma paternine sahiptir. Antenlerin bu özellikleri, GPS alıcılarını karıştırıcı sinyallere de açık hale getirmektedir. Anten dizilerinin kullanımı ile anten dizisi ışıma paterninde sıfır kazanç bölgeleri oluşturmak mümkün olmaktadır. Antenlerden alınan örneklere uygulanacak kompleks ağırlıklandırma çarpanları ile bu sıfır kazanç bölgelerinin karıştırıcılara bakması ile karıştırıcıların belli seviyelere kadar bastırılması mümkün olmaktadır. Bu makale ile aktif GPS anten dizisi tasarım çalışmaları; dairesel polarizasyona sahip yaklaşık kare tasarımlı mikroşerit yama anten, 4 elemanlı dairesel anten dizisi ve 4 kanallı LNA kartı alt başlıkları ile incelenmektedir. Sonuç kısmı ile de yapılan çalışmalar özetlenmektedir. 2 DAİRESEL POLARİZASYONA SAHİP MİKROŞERİT YAMA ANTEN TASARIMI GPS uyduları, sadece askeri alıcılara yönelik L2 bandında, hem askeri hem sivil alıcılara yönelik de L1 bandında yayın yapmaktadır. GPS L1 bandındaki yayının merkez frekansı 1575.42 MHz ve sivil C/A kodu için bant genişliği 2.046 MHz'dir. Uydulardan gelen GPS sinyalleri sağ el dairesel polarizasyona sahiptir. GPS alıcı anten tipi olarak mikroşerit yama anten, üretim kolaylıkları, düşük üretim maliyetleri ve sağladığı performans kriterleri ile sıklıkla tercih edilmektedir. Mikroşerit GPS anteni tasarımımızda, empedans eşleme ve üretim kolaylığı getirdiği için

In this paper, a new compact wideband monopole antenna is presented for wireless communication applications. This antenna comprises of a new radiating patch, a new arc-shaped strip, microstrip feed line, and a notched ground plane. The proposed radiating patch is combined with a rectangular and semi-circular patch and is integrated with a partial ground plane to provide a wide impedance bandwidth. The new arc-shaped strip between the radiating patch and microstrip feed line creates an extra surface on the patch, which helps further widen the bandwidth. Inserting one step notch on the ground plane further enhances the bandwidth. The antenna has a compact size of 16×20×1.6mm3. The measured result indicated that the antenna achieves a 127% bandwidth at VSWR≤2, ranging from 4.9GHz to 22.1GHz. Stable radiation patterns with acceptable gain are achieved. Also, a measured bandwidth of 107.7% at VSWR≤1.5 (5.1-17GHz) is obtained, which is suitable for UWB outdoor propagation. This antenna is...