Synthesis of Serial-Fed Frequency Diverse Arrays With Periodic Triangular Frequency-Modulated Continuous Waveform

Serial‐fed linear frequency diverse arrays for obtaining direction of arrival (DOA) of frequency modulated continuous waveform (FMCW) sources with ambiguity reduction

“…This kind of spatial patterns actually can be used to determine the DOA, since the time delay between the received signals is changing by θ . However, it can be used only for about 30° angle of the incidence, since the received signal from the FDA with the spatial pattern of Figure will be similar at some angles . For example, the received signal at θ = θ 1 is similar to the received signal at θ = − θ 1 , or the received signal at θ = 0° is similar with the received signal at θ = 90°.…”

“…It is worth noting that the phase difference between the elements in the initial case is λ 0 /2 of which the spatial pattern is illustrated in Figure . In Reference , ϕ n was incorrectly considered zero which had fortunately no effects on the shape of the spatial pattern. However, the pattern is shifted 16 854 km on the range axis, which has no effects on the time delays between received pulses.…”

“…Measurement setup for the proposed serial‐fed linear FDA as the receiver is indicated Figure for obtaining the DOA. It is similar to the measurement setup in Reference ; only the receiver and transmitter are substituted by each other. The principles of operation in the transmission and reception modes are similar and same signals will be received after this substitution due to the reciprocity theorem.…”

“…In fact, there is a bijection (one‐to‐one correspondence) between T r and the DOA of the proposed serial‐fed FDA as can be observed in Figure . However, for the serial‐fed FDA in Reference the interval between nearest maximums, , is not a bijective function of DOA as indicated in Figure . Therefore, advantage of the proposed serial‐fed FDA in reducing the ambiguities of obtaining DOA compared with the prior work can be observed in Figure 18, explicitly.…”

“…It is also noteworthy that the practical effects of this miscalculation will only be observed at far ranges wherein the term r 0 / c is comparable with t . A recently introduced application of FDAs is to determine the direction of arrival (DOA) of the incoming wave by using the serial‐fed FDA with a triangular frequency modulated continuous waveform (TFMCW) source . It is also indicated that the spatial power patterns of traditional FDAs can be realized by using serial‐fed FDAs with sawtooth frequency modulated continuous waveform (SFMCW) sources.…”