Log Periodic Antenna (LPDA)
Log Periodic Antenna (LPDA)
Log Periodic Antenna (LPDA)
Log Periodic Antenna (LPDA)
Log Periodic Antenna (LPDA)
專家們長期以來一直警告睡前藍光的危害。（示意圖：shutterstock/達志）
以下內文出自: https://www.chinatimes.com/realtimenews/20250822002926-260408
The Log Periodic Antenna as known as LPDA is a wideband directional antenna that provides gain and directivity combined over a wide band of frequencies.
Both Log-Periodic Antennas and Yagi antennas are high gain directional antennas. The main difference between these antennas is that Log-Periodic Antennas support wider frequency bandwidths and are physically much larger than Yagi antennas.
The log-periodic dipole array typical VSWR is 2:1 and operates over a much wider bandwidth and will have a lower gain for an equivalent number of elements.
With this level of performance, it is ideal for many applications, although a log-periodic antenna will be much larger than a Yagi of an equivalent gain.
想睡好別怕藍光？專家揭睡前看手機未必傷睡眠真相
專家警告睡前藍光會抑制褪黑激素，讓人更清醒、難以入睡，但研究顯示藍光本身未必是睡眠不佳的主因。
《紐約時報》報導，雖然藍光確實會降低褪黑激素，但影響程度取決於使用時間、距離與亮度，然而，目前仍無法確定這些褪黑激素的變化是否足以真正影響睡眠，干擾也可能來自咖啡因、壓力或打鼾等其他因素。
Log Periodic Antenna (LPDA) Log Periodic Antenna (LPDA)雖然還不確定螢幕究竟是透過什麼機制影響睡眠，但亞利桑那大學精神醫學助理教授哈特斯汀（Lauren E. Hartstein）指出，有些研究顯示，人們使用螢幕所作的事，可能扮演了重要角色。
以下內文出自: https://www.chinatimes.com/realtimenews/20250822002926-260408
The Log Periodic Antenna as known as LPDA is a wideband directional antenna that provides gain and directivity combined over a wide band of frequencies.
Both Log-Periodic Antennas and Yagi antennas are high gain directional antennas. The main difference between these antennas is that Log-Periodic Antennas support wider frequency bandwidths and are physically much larger than Yagi antennas.
The log-periodic dipole array typical VSWR is 2:1 and operates over a much wider bandwidth and will have a lower gain for an equivalent number of elements.
With this level of performance, it is ideal for many applications, although a log-periodic antenna will be much larger than a Yagi of an equivalent gain.
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