In this study, the thermal management problem of the modern communication systems with small array sizes is addressed. A novel dual-functional active antenna design strategy is introduced for adjustable frequency of operation and cooling extension at millimeter-wave bands. The concept is based on placing different types of heatsinks on the same patch antenna. The electromagnetic and thermal behavior of the proposed heatsink structures are presented via simulations. Reconfigurable operation at 24, 26, and 28 GHz frequencies with 23 to 28 degrees of extra cooling in the chip as compared to the conventional patch is achieved.@en

This study proposes a dipole antenna with wideband characteristics for microwave imaging (MWI) applications. The wide-band characteristic of the antenna is achieved by reshaping the geometry of the conventional dipole. The dipole is fed by a specially designed balun, together with a ground reflector in order to obtain a high gain unidirectional pattern. The antenna is operating from 2.7 to 5 GHz with a maximum realized gain of 8.39 dBi and |S11| less than -10 dB within this frequency band. The simulation results and evolution of the design procedure are provided. Furthermore, a through- the-wall MWI scenario consisting of thirteen antenna elements, a concrete wall, and two hidden objects behind the wall is implemented to evaluate the performance of the antenna. The 2-D reconstruction results obtained from inversion methods indicate that the proposed antenna is a potential candidate for through- the-wall MWI applications.@en

A novel electromagnetic-thermal codesign and optimization methodology is proposed for thermal management in active finned-heatsink antenna arrays. An innovative complementary split-ring resonator embedded dual-functional (i.e., heat-dissipating electromagnetic-isolation) wall is introduced. For concept demonstration, a two-element unit cell is designed at 26 GHz with the wall in between the antenna elements. It is shown via simulations that the proposed design decreases the junction temperature of the chip driving the elements by almost 40 $^{\circ }$C and 15 $^{\circ }$C as compared with the conventional and finned-heatsink antennas, respectively. Moreover, the port coupling level is reduced to below -25 dB near the operating frequency and a low-complexity beam- switching and nulling function is achieved.

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The present study proposes a dual-polarized bandwidth-enhanced filtering specialized dipole antenna design for 5G by employing a wide printed dipole, filtering resonators, a reflector surface, and specially designed balun structures. Such a configuration is commonly deployed in conventional base stations. To increase the antenna impedance and radiation bandwidth, a specifically designed, wide-printed flared dipole antenna structure is used as the main radiator element. Transmission zeros are introduced at both pass band edges to create a filtering response by engaging parasitic elements. The parasitic element for the higher frequency edge of the filtering is placed close to the maximum amount of the induced current on the radiator at the operating frequency, whereas the parasitic element for the lower frequency edge of the filtering is located close to the perpendicularly polarized structure. The antenna aims to create radiation nulls at the impedance bandwidth limits; therefore, the parasitic arcs are used to create surface currents that cancel the broadside radiation at the limits of the impedance bandwidth. The study illustrates a complete analysis of the broadband printed patch antenna having a filtering effect by parametric investigations on the dimensions and resulting physical phenomenon in detail. To demonstrate the approach, a prototype of the antenna is fabricated and measured. According to the measurement results, the antenna performs 76% impedance bandwidth between 2.49 GHz and 5.59 GHz with |S11| and |S22| < -10 dB by providing exceptional isolation values of |S21| < -20 dB in entire operating band. The fabricated antenna has a stable radiation beamwidth with less than ± 50 variation and the measured gain in the operating frequency is almost constant and equal to 8.2 dBi.

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The present study proposes a dipole filtering antenna with wide-band characteristics for communication. The filtering is achieved by employing parasitic elements and wide-band characteristic is obtained by reshaping the dipole and using specially designed balun structure. One radiation null is optimized at the higher frequency band limit for sharp transition from pass band to stop band via two half-rectangular ring resonators. The antenna operates between 2.6 and 5 GHz and has maximum realized gain of 8.39 dBi. The |S11| is less than -10 dB in the operating frequency band. The simulation results and evolution of the design procedure are presented.@en