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Author: search.filters.author.Promwong, SathapomSubject: search.filters.subject.Friis' transmission formula

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    Evaluation of UWB antennas at 7-9 GHz for short range wireless communications
    (2018-06-08)
    Chinabutr, Chatchawin
    ;
    Promwong, Sathapom
    Ultra wideband (UWB) impulse radio (IR) signals must be able to accomodate its common frequency band at 7.25 GHz to 8.50 GHz. Moreover, the signals should not be distorted too much when they pass through the antennas. Therefore, the transfer function of antennas must to known for the channel performance. In free space loss is usually evaluated by using the formula of Friis's. However, Friis's formula it's not directly applicable to UWB-IR transmission. This study to presentation, the characterization of UWB-IR transmission in FCC with common frequency band that takes into account the transmission waveform in UWB, its consider the distortion due to the antennas and the correlator receiver. Since the antennas are significant pulse-shaping filters in UWB, various kinds of antennas are experimentally examined, especially focusing on the effect of template waveform receiver.
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    Evaluation of ultra wideband impulse radio transmission loss due to laptop computer
    (2009-12-01)
    Sereewattanapong, Thawatchai
    ;
    Promwong, Sathapom
    This paper presents the evaluation of the transmission gain of an ultra wideband antenna on a labtop computer based on the extended Friis' transmission formula. The matched filter is considered at the receiver side to maximize the SNR for evaluation. This technique gives very accurate results and is very useful for the design and evaluation of UWB impulse radio transmission systems, especially for the evaluation of waveform distortion effects. ©2009 IEEE.
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    Indoor propagation channel measurement of ultra wideband antenna with robotic
    (2005-12-01)
    Boonvisat, Satean
    ;
    Promwong, Sathapom
    ;
    Supanakoon, Pichaya
    ;
    Kaewmechai, Sompoph
    ;
    Sitiyopasakul, Pisan
    In this paper, the characterization of ultra wideband (UWB) antenna with robotic is evaluated. The measurement system consists of transmitter (Tx) and receiver (Rx) biconical antennas measured by using a vector network analyzer (VNA). To obtaining the data, measurements were performed at 3 GHz to 11 GHz covered by a VNA, which provided information on the amplitude and phase of the transmission coefficient. Friis' transmission formula is not directly applicable and the waveform distortion may degrade the transmission performance as well. The matched filter is considered at the receiver side to maximize the SNR for evaluation. The power delay profile and the UWB transmission gain, based on the extension of Friis' transmission formula take into account the transmitted waveform and the matched filter into the system for the free space of UWB. The experimental examples using the biconical antenna as the receiver install with robotic are presented in this paper. © 2005 IEEE.