Enlarging or reducing the antenna beam width of antennas can improve the positioning capability of detection systems. A miniaturized and easily fabricated ultra-wideband (UWB) antenna system for long-distance electromagnetic detection is proposed in this article. Two ultra-wideband Vivaldi antennae were designed. One was the transmitting antenna with a beam width of 90° or above, the other was a narrow beam antenna array with beam width less than 10°, as a receiving antenna. Both proposed antennae feature broadside gain diagrams with stable radiation patterns and wideband impedance matching in the frequency range between 2.5 GHz and 4 GHz. After detecting their frequency and time-domain behaviors, the detection system can achieve measurements covering a radius of 30 m.

Shielding effectiveness (SE) evaluation of electrically large enclosures within reverberation chambers (RCs) is standardized procedure for electromagnetic compatibility (EMC) applications. In this work, the potential relationship between SE and electromagnetic resonances has been investigated with respect to the ambiguity in definition of SE for the international standards, e.g., IEC 61000-4-21 or IEEE Std 299.1. From a statistical point of view, we derive the expansions of SE defined by the ratio of the maxima and the averages. To evaluate SE more prudently as well as to obtain a much smaller uncertainty, we can make the tradeoffs for SE, which should be defined as the ratio of the averages for the overmoded frequency and the ratio of the maxima for the undermoded using a common criterion aimed to discriminate the electromagnetic field behavior between the undermoded and the overmoded and also verify the corresponding results by numerical simulations and measurement performed in RC.

A method of measuring the shielding effectiveness of the irregular cavity is proposed in this paper. An electromagnetic topology model of the irregular cavity is established according to the characteristics of the irregular cavity, and the electromagnetic field distribution characteristics inside the irregular cavity are obtained based on the simulation of the field distribution of the irregular cavity. Combined with the test method of regular cavity shielding effectiveness, the characterization and testing methods of the shielding effectiveness of the irregular cavity are given comprehensively, which compared with the conventional testing method, verifies how effectively the shielding effectiveness of the irregular cavity is tested.

To achieve the transfer impedance measurement of electromagnetic interference (EMI) gaskets, a fixture useful up to 18 GHz is developed based on the SAE ARP1705C standard. The radial size of the coaxial section of the fixture is shaped from the perspective of its characteristic impedance and suppression of higher-order modes. Subsequently, a parametric analysis is performed to examine the sensitivity of critical dimensions, and the study analyzes the key factors affecting the voltage standing wave ratio (VSWR) of the fixture and its 50 $\Omega$ resistor. Based on the preceding analysis, two solutions are proposed to improve the VSWR: reducing the length of the 50 $\Omega$ resistor and modifying the shape of the coaxial outer conductor. The ultimate outcome of the transfer impedance measurement fixture yields a VSWR lower than 2.6:1, up to 18 GHz. The functionality of the fixture is demonstrated through the measurement of two gaskets, showcasing its practical utility in engineering applications.

To fulfill the dual-frequency requirements, elements are needed to resonate at two different, independently adjustably frequencies. A low weight, low cost, and easy to fabricate single-layer dual-frequency reflectarray is designed, fabricated, and measured, with gain values of 27 and 29.2 dBi at 20 and 30 GHz, respectively.

When measuring the electromagnetic parameters of flexible material with an air coaxial line, the specimen is prone to bend and deform in the fixture, which results in erroneous results. In order to solve this problem, this paper proposes a new measurement method. Firstly, a rigid material is selected and loaded into the air coaxial line for two-port S parameters measurement. Then, the flexible material is attached to one end of the rigid material and loaded into the air coaxial line together for repeated two-port S parameter measurement. According to the S parameters measured and the two-port network cascading theory, the S parameters of the flexible material separately loaded in the fixture can be deduced. Finally, the electromagnetic parameters of the flexible material can be calculated by the NicolsonRossWeir (NRW) method. Experimental results show that the method proposed is effective and reliable.