A new approach for in‐band radar cross section (RCS) reduction of microstrip patch antenna with preserved radiation features is presented. This aim is achieved by the application of highly absorbing unit cells optimized by particle swarm optimization around the radiating patch of the reference antenna. More than 10 dB in‐band RCS reduction is observed from 2.5 GHz to 3 GHz for both x‐ and y‐polarizations with a −26.4 dB maximum RCS reduction at 2.8 GHz, according to measurement results. A close agreement between the measured and the simulated results shows that the proposed absorbing unit cell is a good candidate to enhance antenna in‐band stealth performance. In addition, with a comparative table, it has been shown that the proposed antenna has much lower in‐band RCS and is more compact than the other antennas proposed in previous literature. The basic benefit of this study is to achieve maximum in‐band RCS reduction, especially at the exact desired frequency without long‐term simulations and time‐consuming design studies.

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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.

While copper is overwhelmingly used as the radiated part in microstrip antenna design studies, the choice of dielectric material offers a wide range of possibilities. At high frequencies, the effect of substrate permittivity on antenna performance is dramatically higher than low frequency microstrip antennas. For this purpose, in this study, a discussion on 4 different dielectric substrates to increase the overall efficiency of conventional sub-6 GHz 5G microstrip antenna is presented. A reference rectangular patch is modeled on FR4, Arlon AD300C, Rogers RO4003C and Mica substrates respectively. The radiating patch sizes are calculated and modeled for each dielectric substrate separately and then optimized for 5.65 GHz. Finally, gain and bandwidth analysis are performed with the help of CST Studio. Arlon AD300C, which is revealed to be the best in performance criteria analysis, is used for the proposed antenna fabrication and the simulated results are verified by bandwidth and gain measurements in a fully anechoic chamber. Finally, the advantages of the proposed antenna over some Sub-6 GHz 5G antennas with randomly selected substrates are confirmed by a comparative table.

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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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