A dual-band dual-polarized microstrip antenna array for an advanced multi-function radio function concept (AMRFC) radar application operating at S and X-bands is proposed. Two stacked planar arrays with three different thin substrates (RT/Duroid 5880 substrates with εr=2.2 and three different thicknesses of 0.253 mm, 0.508 mm and 0.762 mm) are integrated to provide simultaneous operation at S band (3～3.3 GHz) and X band (9～11 GHz). To allow similar scan ranges for both bands, the S-band elements are selected as perforated patches to enable the placement of the X-band elements within them. Square patches are used as the radiating elements for the X-band. Good agreement exists between the simulated and the measured results. The measured impedance bandwidth (VSWR≤2) of the prototype array reaches 9.5 % and 25 % for the S-and X-bands, respectively. The measured isolation between the two orthogonal polarizations for both bands is better than 15 dB. The measured cross-polarization level is ≤-21 dB for the S-band and ≤-20 dB for the X-band. Ⅰ. IntroductionEmbedded in the superstructure of future navy ships will be a variety of antenna arrays that will perform different functions such as radar. The advanced multi-function RF concept (AMRFC) testbed has separate Tx and Rx arrays that were designed for future surface ships in an effort to provide the capability to perform a variety of functions [1]. The performance goal of AMRFC is to provide these functions in a near-concurrent and noninterfering manner [2]. Due to the many advantages of performance improvement for various function systems, the development of modern AMRFC radar systems requires advanced antennas operating in multiband with multi-polarization. In general, a dual-polarized operation can provide more useful information about target features, enhance the isolation between transmitter/receiver, and double the capacity of communication systems by means of frequency reuse [3,4]. A multiband operation, on the other hand, can provide a finer resolution scanning and better penetration and reflection data from various scatterers.Recently dual-band and dual polarized antenna arrays have been widely studied for satellite and wireless communication applications, particularly for synthetic aperture radar (SAR) applications [5～9]. Operating frequencies are usually widely separated (typically some combination of L-, C-, S-or X-bands) and, require different array element spacing to avoid grating lobes. This spacing implies that an interleaved arrangement of elements at each band needs to be optimized. In [5], a dual-frequency (S-band and X-band) antenna for airborne applications was proposed, but this array has narrow bandwidth at both S-and X-bands. A dual-band dual-polarized array design consisting of four double dipole radiators for WLAN applications [6] was suggested to provide very low cross-polarization levels. However, these techniques can not be utilized for the AMRFC radar applications due to their complex structures. A compact three-layer shared-apertur...

As civil infrastructures continue to deteriorate, the demand for structural health monitoring (SHM) has increased. Despite its outstanding capability for damage identification, many conventional SHM techniques are restricted to huge structures because of their wired system for data and power transmission. Although wireless data transmission using radio-frequency techniques has emerged vis-à-vis wireless sensors in SHM, the power supply issue is still unsolved. Normal batteries cannot support civil infrastructure for no longer than a few decades. In this study, we develop a magnetic resonance-based wireless power transmission system, and its performance is validated in three different mediums: air, unreinforced concrete, and reinforced concrete. The effect of concrete and steel rebars is analyzed.

A compact printed multiple‐input multiple‐output (MIMO) antenna with an embedded chip inductor is proposed for a 4G mobile handset application. The proposed MIMO antenna consists of a longer strip with an embedded chip inductor and a shorter radiating strip. The longer radiating strip with a 15‐nH embedded chip inductor has a length of only about 42 mm (∼ 0.1 wavelength at 0.77 GHz), but it supports a wide resonant mode at 0.77 GHz for long‐term evolution (LTE) Band 13 and at 2.35 GHz for WiBro operation. The shorter radiating strip has a length of about 15 mm (about 0.1 wavelength at 2.0 GHz) and provides a wide resonant mode at about 2 GHz for WCDMA operation. The two radiating strips occupy a small printed area of about 720 mm2 on the system circuit board of a mobile handset. The proposed MIMO antenna has an isolation of approximately −17 dB at LTE band 13 and the envelope correlation coefficient (ECC) of the two antennas is always lower than 0.4 over the whole LTE band 13. To evaluate the performance of the proposed antenna, key performance parameters such as the total efficiency, ECC, mean effective gain (MEG), and the MEG ratio are analyzed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:348–352, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25746

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A multiband multiple‐input multiple‐output (MIMO) antenna using polarization diversity for next generation mobile communication is proposed.The MIMO antenna consists of two dual‐band (0.75 GHz/2.5 GHz) dipole antennas with a separation distance of 0.8 mm. One dipole is etched on the top of a two‐layered dielectric substrate with a dimension of 80 × 80 mm2 and the other is printed on the bottom side of the same substrate. They are located orthogonal to one another. Even though the two stacked dipoles are separated by only 0.8 mm, the port‐to‐port isolation is maintained at greater than 20 dB, and the envelope correlation coefficient (ECC) of the two antennas is always lower than 0.2 over the entire frequency band. To evaluate the performance of the proposed antenna, key performance parameters such as the total efficiency, ECC, mean effective gain (MEG), MEG ratio, and actual diversity gain are analyzed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26198