Abstract-This paper presents propagation measurements in the presence of human activity for a 60 GHz channel. Series of 40-min-long measurements of the channel impulse response have been recorded with a sampling period of 1.6 ms, for a total duration of about 20 h. During measurements, the human activity (between zero and 15 persons) was observed with a video camera. The obstruction phenomenon due to the human bodies is characterized in duration and amplitude from the propagation characteristics (attenuation, coherence bandwidth) by means of an appropriate method. The results highlight and quantify the problems due to the human activity for high data rate communication systems. When the direct path is shadowed by a person, the attenuation generally increases by more than 20 dB, for a median duration of about 100 ms for an activity of one to five persons and 300 ms for 11-15 persons. Globally, the channel is "unavailable" for about 1% or 2% of the time in the presence of one to five persons. This channel characterization makes it possible to modelize the temporal variations of the 60 GHz channels. The results also give orientations for the design of high data rate communications systems and networks architectures at 60 GHz.

The aim of the regional research project SIMPAA2, which continues the former national research SIMPAA project, is the realization of a hardware simulator of MIMO propagation channels for UMTS and WLAN applications. The simulator must reproduce the behavior of the radio propagation channel, thus making it possible to test "on table" the mobile radio equipments. The advantages are: low cost, short test duration, possibility to ensure the same test conditions in order to compare the performance of various equipments.

No abstract

This work proposes a contactless multitunable microwave measurement scheme for heartbeat detection. Our system is based on simplicity and the ability of tuning two parameters: frequency and power. Measurements are performed at 2.4, 5.8, 10, 16, and 60 GHz. Operating at 2.4 GHz, the heartbeat signal is detected at different output power levels (from À2 down to À27 dBm). The heart rate variability is extracted for all the measurements.

No abstract

This article presents a contact‐less system to detect the heartbeat activity from a distance of 1 m. The proposed system is based on using a vector network analyzer. Measurements are performed at 16 GHz for different power levels between 0 and −25 dBm. Results for two S‐parameters are obtained and compared to an electrocardiogram simultaneous signal in terms of heartbeat rate and heart rate variability. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2610–2617, 2012; this online at wileyonlinelibrary.com. DOI 10.1002/mop.27152

Figure 6 shows a photograph of the fabricated novel parallel coupler with an area of 30 ϫ 44 mm 2 . CONCLUSIONSA novel high isolation microstrip parallel coupler with -shaped structure has been presented in this article. With -shaped structure, the proposed couplers achieve a physical size reduction of almost 35% with the performance competed with the conventional one. Adopting RPC approach, the isolation is improved greatly. A proposed parallel coupler has been fabricated and measured at 915 MHz. The measurement of the proposed parallel coupler exhibits maximum isolation of Ϫ58.4 dB and directivity of Ϫ40.4 dB at 915 MHz and the isolation is over Ϫ40 dB in 902-928 MHz frequency band. The proposed coupler is compact, easy for fabrication, which can be applied in radiofrequency identification reader system. 2. S. Uysal and H. Aghvami, Synthesis, design and construction of ultrawideband nonuniform directional couplers in inhomogeneous media, IEEE Trans Microwave Theory Tech 37 (1989), 969 -976. 3. M. Dydyk, Microstrip directional couplers with ideal performance via single-element compensation, IEEE Trans Microwave Theory Tech 47 ABSTRACT: The aim of this work is to provide two new schemes for human noninvasive heartbeat activity monitoring using low power microwave noncontact systems and direct conversion architecture. The first system is tested at 2.4 GHz and 5.8 GHz frequencies. Another system, operating at 60 GHz, is demonstrated where higher heartbeat sensitivity detection is achieved. ABSTRACT: A compact printed monopole antenna having small dimensions (22 ϫ 9.5 ϫ 1.6 mm 3 ) for the WLAN bands is presented. With the use of a plated-through via connecting a rectangular patch with a meandered strip on the both sides, the impedance matching in multiband operation covering 2.4, 5.2, and 5.8 GHz bands is obtained. A theoretical and experimental investigation of the antenna is given.

No abstract