Solving the problems of a single antenna frequency modulated CW radar

Polarimetric Calibration of the Ku-Band Advanced Polarimetric Radar Interferometer

“…This arrangement ensures a low level of polarimetric crosstalk because only one combination is acquired at each time and the antennas are physically separated. Additionally, the separation of transmitting and receiving antennas increases the transmit-receive isolation, a fundamental requirement for FMCW performance [45], [46], [57]. The disadvantage of this configuration is that certain combinations of channels i and j will be separated by a baseline: These antennas can be replaced by an equivalent antenna located at the midpoint between transmitter and receiver [37].…”

Etched ring absorbing waveguide filter based on a slotted waveguide antenna response

“…From this, the electrical characteristics ω 0 , g(ω 0 ) and ∂b/∂ω| (ω=ω0) of each slot were determined, and parameters for three equivalent circuit representations calculated using (1). Next, these calculated circuit values where entered in a single circuit representation of the three slot cascaded structure, as shown in Fig.…”

“…Introduction: FMCW radar reflected power cancellers (RPCs) have for many years relied on closed-loop controllers for active cancellation [1]. Recently, a passive balanced topology to cancel transmitter leakage and antenna reflections, was suggested for MMIC implementation [2].…”

“…The implementation of such a load is no trivial task, as the input impedance has to match that of the antenna very closely over the whole band of interest. In this paper, it is shown that the slotted waveguide antenna, often used in high frequency FMCW radars [1] [3], allows for a particularly interesting implementation of such a system, as a load can be designed which approximates the input impedance of the antenna very closely. By periodic cascading of some lossy microwave structure in waveguide, each having transmission and reflection characteristics similar to a single radiating slot of the antenna, a load is obtained which is not only similar to the antenna in construction, but also in input impedance.…”

A Compact Ka-Band Doppler Radar Sensor for Remote Human Vital Signal Detection

“…Ka-bands, such as 24 GHz in the ISM (Industrial, Scientific, and Medical) band, are widely used because a compact-sized radar can be achieved due to the size reduction of the passive and active components [7]. A single antenna can reduce the module size greatly because the antenna is one of the largest components in microwave Doppler radar [8]. Also, the circulator can be replaced with a coupler, such as a Lange coupler, which can be integrated onto the semiconductor [9], [10].…”