Path-loss measurements are determined for a test client device moving along a path in a field test environment in which field Wi-Fi mesh network nodes are distributed. The path-loss measurements are reproduced in a field-to-lab test environment that includes a test client device disposed in an electromagnetically-isolated chamber and field test Wi-Fi mesh network nodes disposed in respective electromagnetically-isolated chambers. The test client device and the field test Wi-Fi mesh network nodes are in wired or wireless communication with each other via signal lines. A programmable attenuator is electrically coupled to each signal line. The attenuation of each programmable attenuator is varied to reproduce the path-loss measurements from the field test environment. Path-loss measurements at the location of each field Wi-Fi mesh network node are also reproduced with the programmable attenuators to reproduce the field Wi-Fi mesh network node configuration.

A measurement system utilizing metasurfaces and compressive sensing is provided that measures specular and diffuse RF reflection properties of a sample omnidirectionally across a broad frequency regime in a monostatic, bistatic, or BRDF sense. The measurement system may be used to measure the full hemispherical (or spherical) reflection from a target that has been illuminated in a monostatic or bistatic case. The measurement system may also be used to measure the full BRDF of a sample or spatially complex bistatic reflections from a sample.

A method of preventing loss of headphones configured to communicate with a cell phone enables an alarm setting using an app on the cell phone; the app responding by continuously measuring a received magnitude of a wireless signal transmitted between the cell phone and the headphones. If the measured received magnitude is lower than a predetermined threshold value for a first predetermined time, an audible alarm is activated at the headphones. The continuous measurement and the activation of the alarm dependent on the measured received magnitude occur automatically, independent of any user interaction with the app after the alarm setting enablement. Another method addresses a corresponding issue in a similar way to prevent loss of one earbud of a pair.

A method of declaring Equivalent Isotropically Radiated Power (EIRP) for an operating frequency band of a base station. The method includes: declaring a first EIRP for a first frequency of the operating frequency band, declaring a second EIRP for a second frequency of the operating frequency band, and declaring a third EIRP for a third frequency of the operating frequency band, wherein the third frequency is between the first frequency and the second frequency, and wherein the second frequency is higher than the first frequency.

Disclosed are techniques for handling of radio frequency (RF) front-end group delays for roundtrip time (RTT) estimation. In an aspect, a network node transmits first and second RTT measurement (RTTM) signals to a user equipment (UE) and receives first and second RTT response (RTTR) signals from the UE. The network node measures the transmission times of the RTTM signals and the reception times of the RTTR signals, and the UE measures the transmission times the RTTM signals and the transmission times of the RTTR signals. The group delays of the transmit/receive chains of the network node and the UE are determined for one set of transmit/receive chains based on the first RTTM signal and first RTTR signal. The group delays of the transmit/receive chain used for the second RTTM signal and the second RTTR signal are determined relative to the group delay of the one set of transmit/receive chains.

A sensor system for determining a condition associated with a piston rod of a reciprocating system includes an interrogator system having a first antenna. The sensor system further includes a second antenna separated from the first antenna by an air gap distance. The second antenna is configured to be coupled to the piston rod of the reciprocating system. The second antenna is a patch antenna and is configured to communicate with the first antenna through a range of translational movement relative to the first antenna. The sensor system further includes a radio frequency sensor coupled to the second antenna. The radio frequency sensor is configured to be coupled to the piston rod of the reciprocating system, measure a characteristic associated with the piston rod of the reciprocating system, and transmit data associated with the characteristic to the first antenna of the interrogator system through the second antenna.

A communication device includes: an optical-communication circuit that is capable of performing optical communication with a different communication device and transmits a first electric signal to the different communication device at a startup time of the communication device; an electro-communication circuit that is capable of performing electro communication with the different communication device and receives a second electric signal transmitted from the different communication device in response to the first electric signal; and a control circuit that transmits error information indicating an error in the optical communication to a device after the second electric signal is received by the electro-communication circuit.

A communication device includes: an optical-communication circuit that is capable of performing optical communication with a different communication device and transmits a first electric signal to the different communication device at a startup time of the communication device; an electro-communication circuit that is capable of performing electro communication with the different communication device and receives a second electric signal transmitted from the different communication device in response to the first electric signal; and a control circuit that transmits error information indicating an error in the optical communication to a device after the second electric signal is received by the electro-communication circuit.

A directional coupler disclosed herein may include a main line provided on a substrate, the main line having a first end connected to an input port and a second end connected to an output port. The coupler may include a coupled line disposed on the substrate, the coupled line having a first end connected to a coupled port and a second end to an isolated port. The main line is electrically isolated from the coupled line. The coupled line includes multiple turns forming a winding, and a portion of the winding overlaps with the main line. The coupled line forms a plurality of windings inductively coupled with the main line. The main line and the coupled line are routed to propagate electric signals on both lines in a same direction, and enhance inductive coupling by mutual inductance.

The invention provides an in-line power monitor for an RF transmission line that is capable of being calibrated in-line during live conditions at the exact power level and frequency where it is used. This device uses forward and reflected directional couplers and a non-directional coupler to sample the RF voltage on the transmission line. The RF voltage of the forward and reflected channels are each split into two paths, one going to a test port and the other leading to additional circuitry which prepares the signals of the forward and reflected channels for output to power displays. Additionally, the monitor allows the user to compensate for any voltage offsets introduced by various circuitry components. Further, the monitor also allows to user to individually calibrate the output of the forward and reflected channels by applying an adjustable gain ratio correction to each channel.