Prospects of FMCW-based frequency diverse array radar

The linear frequency modulated (LFM) frequency modulated continuous wave (FMCW)-based frequency diverse array (FDA) radar concept is investigated in detail. The radar operates as a linear pulsed FMCW/FDA in the transmission (TX) mode while it operates as a pulsed FMCW/phased array (PA) in the receiving mode. The issues such as low signal-to-noise ratio (SNR) of FDA, the time-angle scanning and time-range ambiguities are studied. It is shown that the local instantaneous frequency bandwidth is much smaller than the radio frequency (RF) deviation of LFM. Positive and negative slope TX/RF locations offer frequency diversity. Time domain and frequency domain signal processings are described. A Ku band direct digital synthesis-based FMCW/FDA radar example based on the cumulative detection scheme is given and compared with an equivalent FMCW/PA radar

Range and Angle Measurement in a Linear Pulsed Frequency Diverse Array Radar

The range-angle coupling in Frequency Diverse Array (FDA) radar is uniquely solved. The array operates as a linear pulsed FDA in the transmission (TX) mode while it operates as a pulsed phased array (PA) in the receiving (RX) mode. The duration of FDA TX pulse is chosen as minimum. A novel radar concept is proposed. It is shown that FDA waveform can be further compressed by matched filtering (MF)

Narrow band wide angle scanning circular frequency diverse array radar

One dimensional Linear Frequency Diverse Array (FDA) is extended to a circular two dimensional FDA array (CFDA). The CFDA operates as a pulsed FDA in the transmission (TX) mode while it operates as a pulsed phased array (PA) in the receiving (RX) mode. CFDA has a constant antenna pattern steering property in the plane of the circle while it has FDA scanning property in the orthogonal plane. This is achieved by assigning frequency offsets to the elements of the array cosinusoidally which changes with the steer angle, making the CFDA narrow band. The matched filter (MF) for pulse compression is also designed for a particular direction of interest

A Multi-Center Study on the Efficacy of Eltrombopag in Management of Refractory Chronic Immune Thrombocytopenia: A Real-Life Experience

Objective: The aim of the present study was to evaluate the efficacy and safety of eltrombopag, an oral thrombopoietin receptor agonist, in patients with chronic immune thrombocytopenia (ITP)

A Multi-Center Study on the Efficacy of Eltrombopag in Management of Refractory Chronic Immune Thrombocytopenia: A Real-Life Experience

Objective: The aim of the present study was to evaluate the efficacy and safety of eltrombopag, an oral thrombopoietin receptor agonist, in patients with chronic immune thrombocytopenia (ITP). Materials and Methods: A total of 285 chronic ITP patients (187 women, 65.6 \%; 98 men, 34.4\%) followed in 55 centers were enrolled in this retrospective cohort. Response to treatment was assessed according to platelet count (/mm(3)) and defined as complete (platelet count of >100,000/mm(3)), partial (30,000-100,000/mm(3) or doubling of platelet count after treatment), or unresponsive (<30,000/mm(3)). Clinical findings, descriptive features, response to treatment, and side effects were recorded. Correlations between descriptive, clinical, and hematological parameters were analyzed. Results: The median age at diagnosis was 43.9 +/- 20.6 (range: 3-95) years and the duration of follow-up was 18.0 +/- 6.4 (range: 6-28.2) months. Overall response rate was 86.7\% (n=247). Complete and partial responses were observed in 182 (63.8\%) and 65 (22.8\%) patients, respectively. Thirty-eight patients (13.4\%) did not respond to eltrombopag treatment. For patients above 60 years old (n=68), overall response rate was 89.7\% (n=61), and for those above 80 years old (n=12), overall response rate was 83\% (n=10). Considering thrombocyte count before treatment, eltrombopag significantly increased platelet count at the 1st, 2nd, 3rd, 4th, and 8th weeks of treatment. As the time required for partial or complete response increased, response to treatment was significantly reduced. The time to reach the maximum platelet levels after treatment was quite variable (1-202 weeks). Notably, the higher the maximum platelet count after eltrombopag treatment, the more likely that side effects would occur. The most common side effects were headache (21.6\%), weakness (13.7\%), hepatotoxicity (11.8\%), and thrombosis (5.9\%). Conclusion: Results of the current study imply that eltrombopag is an effective therapeutic option even in elderly patients with chronic ITP. However, patients must be closely monitored for response and side effects during treatment. Since both response and side effects may be variable throughout the follow-up period, patients should be evaluated dynamically, especially in terms of thrombotic risk factors