In this paper, a novel high isolation and high-capacitance-ratio radio-frequency micro-electromechanical systems (RF MEMS) switch working at Ka-band is designed, fabricated, measured and analyzed. The proposed RF MEMS switch mainly consists of a MEMS metallic beam, coplanar waveguide (CPW) transmission line, dielectric layer and metal–insulator–metal (MIM) fixed capacitors. The measured results indicate that the insertion loss is better than 0.5 dB at 32 GHz, and the isolation is more than 35 dB at the resonant frequency. From the fitted results, the capacitance ratio is 246.3. Compared with traditional MEMS capacitive switches, this proposed MEMS switch exhibits a high capacitance ratio and provides a wonderful solution for cutting-edge performance in 5G and other high-performance applications.

This paper proposes a radiating pattern reconfigurable antenna by employing RF Micro-electromechanical Systems (RF MEMS) switches. The antenna has a low profile and small size of 4 mm × 5 mm × 0.4 mm, and mainly consists of one main patch, two assistant patches, and two RF MEMS switches. By changing the RF MEMS switches operating modes, the proposed antenna can switch among three radiating patterns (with main lobe directions of approximately −17.0 • , 0 • and +17.0 • ) at 35 GHz. The far-field vector addition model is applied to analyse the pattern. Comparing the measured results with analytical and simulated results, good agreements are obtained.

The research on reconfigurable antennas has some disadvantages such as low working frequency and large size. This paper presents a Ka-band patch antenna with pattern reconfigurability using RF MEMS switches. The antenna contains one main patch, two sub-patches, two parasitic patches, and two RF MEMS switches. By controlling the states of the RF MEMS switches, the antenna can achieve three different radiation patterns (−8°, 0°, and +8°) at 35 GHz. The pattern analysis was based on the electric field vector addition method. The analytical, simulated, and measured results agree well with each other. Due to its compact and thin structure of 3.7 mm × 5.2 mm × 0.4 mm, this antenna can be applied in fields such as satellites, smartphones, etc.

In this paper, a novel ultra-wideband (UWB) printed antenna with quadruple band-notched characteristics is proposed and investigated. The quadruple band rejections are achieved by etching two interdigital capacitance slots on each side of the ground plane, embedding a curled C-shaped slot on the circle patch, and adding a curled split-ring resonator on the backside of the antenna. Interdigital inductance slots can obtain a narrower notched band than general structures due to their high inductance, thereby preserving some valuable frequencies. Adjusting the tail branch’s length and distance of the curled C-shaped slot and the curled split-ring resonator can control the notch frequency and width. Finally, the proposed antenna operates from 2.9–11 GHz (VSWR < 2) with four band stops (VSWR > 2) for rejecting WiMAX, WLAN, and downlink of X-band satellite communication. Furthermore, the difference between the experimental results and the expected value is less than 3%. The proposed antenna can accurately filter out narrow-band signals.

A Ka-band CPW-Slot-Couple (CSC) fed microstrip antenna with enhanced bandwidth and gain is presented in this paper. To simplify the feed network, the matching slots are designed at the end of the CPW. Consequently, the patch antenna is designed with a low profile, which has a size of 7.2 × 32.6 × 0.508 mm3. Characteristic mode analysis (CMA) is applied to illustrate the principle of the enhancement of the band with the form characteristic mode point of view. A slot based on inductive loading is employed on the parasitic patch to move the resonant frequency of CM3 to the resonant frequency of CM2 for enhanced bandwidth, which avoids introducing additional impedance matching networks. The measured results show that the bandwidth of the proposed monolayer antenna is 14.18% from 24.84 to 28.6 GHz and the peak gain is 7.9 dBi. Due to its attractive properties of low profile, compact configuration, wide band, and high gain, the proposed antenna could be applied to miniaturized millimeter-wave applications.