This research paper introduces a ultra-wideband (UWB) multiple input multiple output (MIMO)/diversity antenna with three rejected bands using one compact electromagnetic band gap (EBG) structure. The suggested EBG structure rejects three bands at WiMAX, WLAN, and the X-band within the passband of the UWB antenna. To achieve compactness in the conventional EBG structure, two via and square slots are introduced. This structure contributes to better impedance matching by using tapered feedline and slots in the radiating patch. To improve the isolation among all four compact UWB monopoles, decoupling strips are extended from the ground plane. Furthermore, the |S21| is below 17 dB in between the antenna elements and the envelope correlation coefficient is below 0.5, which are tolerable values within the UWB range. Furthermore, different MIMO/diversity characteristics are also discussed. An FR-4 substrate with dimensions of 38 × 45 × 1.6 mm3 is used for the fabrication of the suggested structure.

This paper presents a miniature monopole reader antenna for tri-band radio frequency identification (RFID) portable devices. The proposed antenna operates at the main RFID frequencies and can alleviate and compensate for the shortcomings of a single-band antenna. An additional rectangular stub couples with the bent monopole antenna, allowing the latter to resonate at the RFID bands at 902–928 MHz, 2.4–2.48 GHz, and 5.725–5.875 GHz. By bending the feedline, the dimensions of the miniature antenna are reduced to 115.5 × 20 × 1.6 mm3, facilitating its integration into portable devices. The measured bandwidths(return loss < −10 dB) of the proposed antenna are 677, 580, and 250 MHz in the three operating bands, 883–1560 MHz, 2.31–2.89 GHz, and 5.65–5.9 GHz, respectively, with high-gain characteristics. An experimental study of a fabricated prototype of the optimized antenna is performed, and the results verify its good performance.

This paper presents the design fabrication and measurement of a nanogap radio frequency microelectromechanical system (RF MEMS) metal-contact switch. The prosed device generates a relatively high contact force with a low actuation voltage using a dielectric layer between the actuation electrode and the moveable beam. The actuation voltage is decreased with good reliability of the device by scaling down the gap. Beam geometry optimization allowed reaching 126 micronewtons contact force with only 10 V bias voltage. The fabricated miniature switch (80 × 50 × 0.95 µm) has indeed a pull-down voltage of 6 V and a contact resistance <2 Ω with 10 V bias applied. By measuring the S-parameters, the up-state capacitance has been fitted to 22 fF. The remarkable figure-of-merit Ron × Cup = 44 fs reflects the good performance of the device. A cycling test showed the device operated for 90 min without any charging problem noted.

A 15–32 GHz miniature single-balanced gate mixer is proposed and analyzed. It achieves a smaller chip area with acceptable conversion gain and port-to-port isolation. In addition, the design procedure is described in detail. This mixer, fabricated in 90 nm digital CMOS technology, demonstrates a measured conversion loss of 1 dB and higher than 30 dB RF-to-LO port isolation from 17 to 32 GHz, at a local oscillator (LO) driver power of −4.3 dBm. The total dc power consumption is only 6 mW from a 1.2 V supply, including output buffer. The low dc power consumption and LO driver power reduce the power budget, and the proposed miniature rat-race hybrid facilitates integration in a receiver.

The role and place of children is frequently overlooked in archaeology. Here Robert Park presents an intriguing analysis of the toys of childhood found in Inuit societies in Canada and Greenland, and assesses how such objects inform on the role of children in Arctic societies.