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In order to curtail mutual coupling between two closely spaced microstrip monopole antennas operating at frequencies 28 GHz and 39 GHz, the concept of electromagnetic cloaking is applied by utilizing elliptical metasurfaces. In this paper, we show that by enveloping the monopole antennas with the specifically engineered metasurface cloaks, not only is there a significant reduction in the mutual electromagnetic interaction but also restoration in the radiation patterns are observed, as if the antennas were completely isolated from each other. The decoupling effect is seen in the reduction of mutual S-parameters. This enables the antennas to radiate independently even though they are placed in a very close proximity. 

Abstract We present the results of a search for gravitational-wave transients associated with core-collapse supernova SN 2023ixf, which was observed in the galaxy Messier 101 via optical emission on 2023 May 19, during the LIGO–Virgo–KAGRA 15th Engineering Run. We define a five-day on-source window during which an accompanying gravitational-wave signal may have occurred. No gravitational waves have been identified in data when at least two gravitational-wave observatories were operating, which covered ∼14% of this five-day window. We report the search detection efficiency for various possible gravitational-wave emission models. Considering the distance to M101 (6.7 Mpc), we derive constraints on the gravitational-wave emission mechanism of core-collapse supernovae across a broad frequency spectrum, ranging from 50 Hz to 2 kHz, where we assume the gravitational-wave emission occurred when coincident data are available in the on-source window. Considering an ellipsoid model for a rotating proto-neutron star, our search is sensitive to gravitational-wave energy 1 × 10⁻⁴M_⊙c²and luminosity 2.6 × 10⁻⁴M_⊙c²s⁻¹for a source emitting at 82 Hz. These constraints are around an order of magnitude more stringent than those obtained so far with gravitational-wave data. The constraint on the ellipticity of the proto-neutron star that is formed is as low as 1.08, at frequencies above 1200 Hz, surpassing past results.