In this study, a novel double‐negative compact metamaterial (MM) that can operate in Ku‐band (12 GHz) is designed and fabricated. It is shown that the proposed structure can be used as a MM for a wide bandwidth of 6 GHz. A double electromagnetic lens layer is then formed using this MM unit cell in an array. Afterwards, obtained lens layers are used together with a conventional microstrip patch antenna (CMPA) operating at 12 GHz. The effect of the MM on the antenna gain and directivity is examined. The CMPA and MMs are fabricated, and measurements are performed in Akdeniz University Microwave Laboratory and simulated with Microwave Studio by Computer Simulation Technology. 71% and 50% improvement in antenna gain and directivity are obtained by using it as a double MM lens layer.

Reverberation chambers (RCs) are cheaper alternatives to anechoic chambers (ACs), and they are mainly made up of metal (ideally perfect and smooth) covered rooms. Their designs are not sophisticated as in AC, and EMC tests at precompliance level can be applied within a certain interval of error. For applying EMC tests to any equipment under test (EUT), the electric field uniformity in the room must be satisfied within a certain error. The volume having a uniform electric field is called as working volume (WV) where EUT for being subjected to EMC tests will be placed in. Positions and dimensions of scatterer such as Tx antenna that must be in the room determine the dimension of WV. Classically, position of transmitting antenna is changed continuously and randomly till obtaining WV and this process ends at any time within 3 days. Industry is always hurried and wants to know when to start testing. In this study, a fast and novel method with data mining has been proposed for overcoming this problem, and it achieves a success rate of 96% in 4‐5 hours. The model was tested for 10 different angles of rotation of the stirrer and 97% accuracy was achieved.

High antenna directivity is generally desirable for wireless communication systems, whether terrestrial or based on satellites. Most of the solutions proposed for improvement of the directivity of microstrip patch antennas were to design array of several antennas. The particular disadvantage of this method comes from the feeding of each antenna and also from the coupling between each element. A suitable model to eliminate these two disadvantages is to use a separate superstrate structure. For this purpose a Left-Handed medium (LHM) superstrate used and presented in this study. Both the reference antenna and proposed antenna are simulated, fabricated, and tested. The simulation results show good agreement with the measurement results. It is observed that the reference antenna directivity increased by 1.72 dB with the proposed LHM superstrate according to the measurement results for 12 GHz operating frequency.

Bu çalışmada Ku band mikroşerit yama anten yönlendirici kazanç iyileştirmesi için Bölünmüş Halka Rezonatör (BHR) metamateryal (MM) lens kullanımı gösterildi. Ku bandında odaklama elde edebilmek için aynı bantta negatif kırılma indisli bir BHR metamateryal lens tasarlanıp referans antenin ışıma doğrultusunda yarım dalga boyu uzaklığına yerleştirilerek benzetim ve ölçüm sonuçları ayrı ayrı elde edildi. Bu şekilde referans antenin yönlendirici kazancında ölçüm sonuçlarına göre 1.52 dBi'lık bir artış olduğu tespit edildi. Bu çalışmada, alt tabaka ve üst tabaka için aynı dielektrik malzemeler kullanılmış ve böylece MM lens tabakasının kazanç artırımına yararlı etkisi daha net olarak gösterilmiştir. Ayrıca düşük anten boyutu için MM lens katmanının toplam boyutu, referans antenin yama boyutuyla hemen hemen aynıdır. Bu çalışmayı literatürdeki benzer diğer çalışmalardan avantajlı kılan bir diğer husus, daha az sayıda metamateryal birim hücreden oluşan lens katmanı kullanılmasıdır.

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