A reconfigurable power-dividing scheme has been developed, employing coupled line couplers and mode control switches. Depending on the operating conditions of the switches, it provides two different operating states: two-way Wilkinson equal-split power divider or oneway signal path, which directs all input power to one output port. Input and output matching conditions at both operating modes were accomplished by utilising appropriate even-and odd-mode characteristic impedances of the coupled line coupler.
This paper presents 77-GHz CMOS radar transmitter and receiver chips equipped with monopole feeders for use in frequency-modulated continuous-wave radar systems. The on-chip monopole feeder can feed not only the aperture of waveguides but also the slots on planar circuits by simply attaching the chips to a printed circuit board using a low-cost non-conductive epoxy. With the aid of a high ratio multiplier and the proposed on-chip feeder, a radar system can easily be integrated without needing to use precise and expensive millimeter-wave packaging technologies. In order to experimentally confirm this, the chips integrated with waveguides are first measured and a full radar system integrated on the planar circuit is evaluated using the microstrip patch antennas. Finally, with the benefit of compact integration technology, the design of a five-channel 3-D environmental sensing radar for small-unmanned aerial vehicles is presented. INDEX TERMS Radar, CMOS, frequency multiplier, millimeter-wave (mm-wave) packaging, on-chip feeder.
This letter presents the in-plane poling in electro-optic (EO) polymer modulators with conductivity dependency of core and claddings eliminated. A Mach-Zehnder (MZ) modulator with a highly conductive EO polymer, AJLS102/APC, is realized and poled by the in-plane coplanar waveguide poling electrode. Vπ of 7.7V in a single-arm poled MZ (3.8V for push-pull operation) is achieved and the evaluated r33 is 65pm∕V. Combined with the r33’s of the previously measured single layers and MZ modulators using two other EO polymers, this experiment proves that the r33 proportional to the single layer r33 can be achieved in an in-plane MZ device regardless of the material conductivities.
In this study, we propose a W-band frequency modulated continuous wave(FMCW) radar altimeter that can measure the altitude based on the frequency differences of transmitted and received signals. This W-band FMCW system is powered by an altitude control algorithm, which we propose to help prevent collisions of drones with obstacles in real deployment by measuring the relative altitude. It is shown that this algorithm enables the drone to be positioned within a 3 % error of altitude from the desired input height. The chip used in the W-band transmitter and receiver was fabricated using a 65-nm CMOS process, and a horn antenna was directly fed by incorporating an embedded waveguide feeder into the chip [1]. The clutter spectra observed in terrains including soil, grass, and calm lake water were measured and compared, confirming the reflectivity characteristics of various surfaces of different water contents.
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