Abstract: An electrical device includes a device housing having an internal cavity. The electrical device includes a device sensor in the internal cavity. The electrical device includes a control circuit board in the internal cavity. The control circuit board includes a sensor circuit coupled to the device sensor. The control circuit board includes a ground circuit and a communication circuit with a feed circuit. The electrical device includes an antenna assembly coupled to the control circuit board. The antenna assembly includes a substrate mounted to the control circuit board and an antenna element extending along at least one surface of the substrate. The antenna element is coupled to the feed circuit and the ground circuit. The antenna assembly includes a switchable matching circuit coupled to the antenna element. The switchable matching circuit changes a feed impedance of the feed circuit.

Abstract: An antenna assembly includes a metasurface antenna unit including a radiating structure, a feeding structure, and a grounding structure therebetween. The radiating structure includes radiating elements arranged in an m×n grid of m rows of radiating elements and n columns of radiating elements, where n is greater than m. The radiating elements are separated by radiating slots with edges of the radiating elements facing each other across the radiating slots. The grounding structure includes a ground plane having a coupling aperture therethrough. The feeding structure includes a single strip feedline for feeding the radiating elements. The strip feedline passes across the coupling aperture and feeds the radiating structure through the coupling aperture. At least one of the radiating elements is fed through at least one other radiating element across the corresponding radiating slot.

Abstract: An antenna device includes a main circuit board, a first-type antenna ground-coupled to the main circuit board, and a second-type antenna ground-coupled to the main circuit board. The first-type antenna has a ground structure. The second-type antenna is spaced apart from the first-type antenna and an operating bandwidth of the second-type antenna is greater than an operating bandwidth of the first-type antenna.

Abstract: A coupling circuit (22) for a radiofrequency (RF) receiver (10) has an attenuator (38) and a resonator (40). Three resistors (42,44,46) of attenuator (38) provide a lossy resistive isolation between a first mixer (20) and a crystal filter (24) of (RF) receiver (10) for undesired signals such as noise and harmonics. Thus, signal reflections between first mixer (20) and crystal filter (24) are absorbed for these undesired signals. However, for desired signals at an intermediate frequency (IF), resonator (40) has an inductor (54) and a capacitor (56) to resonate with such desired signals at the IF. As a result of resonance, resistors (42,46) are isolated to alleviate attenuation of the desired signals.