A dual-band polarizer is presented that converts linear polarization into circular polarization with orthogonal handedness in the satcom bands 19.7-20.2 GHz and 29.5-30 GHz. The polarizer consists of three identical cascaded perforated metallic screens, whose perforations are periodically repeated crosses of two sizes. Unlike previously reported dual-band polarizers, our design is fully metallic, which results in low losses and makes it suitable for space applications. A prototype of the polarizer with 20×20 unit cells is manufactured, and the measurement results agree well with the simulated results. In the nominal satcom bands, the measured axial ratio and the insertion loss are better than 1.7 dB and 0.67 dB. In the bands 18.9-20.3 GHz and 29.1-30.1 GHz, the measured axial ratio and insertion loss are below 3 dB and 1 dB.

Mutual coupling, or equivalently, the isolation between antennas, is a key parameter in antenna system design. In this work, a new quantity is proposed to obtain spatial information about mutual coupling. The new quantity is named the weak-coupling density. This quantity is a real-valued scalar and can be visualized as a three-dimensional density in space. It is also shown that there is a strong correlation between regions with a positive (negative) weak-coupling density and decreasing (increasing) the coupling when placing an absorber in that region. This predictive ability is a useful feature, which is tested here for three numerical cases. The results are robust to the shape of the platform, and it persists over neighboring frequencies. By placing absorbers based on the weak-coupling density, it is possible to reduce the required amount of absorbers to obtain a certain mutual coupling reduction. The visualization results and predictions of absorber positions are compared with a Poynting vector based method. Placing absorbers based on the weak-coupling density had a larger impact on the mutual coupling, compared to the predictions with the Poynting vector based method in the investigated cases.

Mutual coupling, or equivalently, the isolation between antennas, is a key parameter in antenna system design. In this work, a new quantity is proposed to obtain spatial information about mutual coupling. The new quantity is named the weak-coupling density. This quantity is a real-valued scalar and can be visualized as a three-dimensional density in space. It is also shown that there is a strong correlation between regions with a positive (negative) weak-coupling density and decreasing (increasing) the coupling when placing an absorber in that region. This predictive ability is a useful feature, which is tested here for three numerical cases. The results are robust to the shape of the platform, and it persists over neighboring frequencies. By placing absorbers based on the weak-coupling density, it is possible to reduce the required amount of absorbers to obtain a certain mutual coupling reduction. The visualization results and predictions of absorber positions are compared with a Poynting vector based method. Placing absorbers based on the weak-coupling density had a larger impact on the mutual coupling, compared to the predictions with the Poynting vector based method in the investigated cases.

Mutual coupling, or equivalently, the isolation between antennas, is a key parameter in antenna system design. In this work, the previously defined impedance density is generalized, and it is demonstrated how it can be used to obtain spatial information about the mutual coupling. The generalized impedance density is a real-valued scalar and it can be visualized as a three-dimensional density in space. It is shown that there is a strong connection between regions with a positive (negative) generalized impedance density and a decrease (increase) of the coupling when an absorber is placed in that region. This predictive ability is a useful feature, which is tested for three numerical cases. The results are robust to the shape of the platform, and it can be compared across frequencies. By placing absorbers based on the generalized impedance density, it is possible to reduce the required amount of absorbers needed to obtain a certain reduction in mutual coupling. The visualization results and predictions of absorber positions are compared with a Poynting vector based method. Placing absorbers based on the generalized impedance density had a larger impact on the mutual coupling, compared to the predictions with the Poynting vector based method in the investigated cases.<br>

Mutual coupling, or equivalently, the isolation between antennas, is a key parameter in antenna system design. In this work, the previously defined impedance density is generalized, and it is demonstrated how it can be used to obtain spatial information about the mutual coupling. The generalized impedance density is a real-valued scalar and it can be visualized as a three-dimensional density in space. It is shown that there is a strong connection between regions with a positive (negative) generalized impedance density and a decrease (increase) of the coupling when an absorber is placed in that region. This predictive ability is a useful feature, which is tested for three numerical cases. The results are robust to the shape of the platform, and it can be compared across frequencies. By placing absorbers based on the generalized impedance density, it is possible to reduce the required amount of absorbers needed to obtain a certain reduction in mutual coupling. The visualization results and predictions of absorber positions are compared with a Poynting vector based method. Placing absorbers based on the generalized impedance density had a larger impact on the mutual coupling, compared to the predictions with the Poynting vector based method in the investigated cases.<br>