Time-Domain Measurement of the Frequency-Dependent Delay of Broadband Antennas

Abstract

Abstract-We present a new time-domain technique for direct measurement of the frequency-dependent delay of broadband antenna structures. By utilizing a series of fixed-bandwidth, variable center frequency waveforms synthesized in a photonics-based electromagnetic pulse shaper, we perform high time resolution ( 54 ps over 10 ns) measurements of several broadband antenna structures. Our results show excellent agreement with the delay extracted via time-domain impulse response measurements, however, compared to conventional impulse response measurements, our method ensures a higher signal-to-noise ratio because it relies on several relatively narrowband measurements as opposed to a single broadband measurement. In addition, the delay uncertainty in our technique ( 54 ps) is significantly below that of impulse response measurements ( 300 ps) where numerical differentiation of noisy data leads to substantial errors. Our technique is well suited as a diagnostic tool for future variable-frequency fixed-bandwidth systems.

Ultra-Wideband (UWB) Communications Channel – Theory and Measurements

“…Moreover, a procedure is proposed in (106) how to design a UWB antenna with minimum pulse distortion. The frequency-dependent delay of UWB antennas is investigated in (107). A strong agreement with the delay extracted via time-domain impulse response measurements is shown in (107).…”

Analysis of Impulse Dispersion for IR-UWB Antenna Using Time-Frequency Analysis

“…최근에 UWB 기술은 표면 투과 레이더, 비파괴 시 험장비, 산업용 센서, 위치 정밀 추적 장치, 의료 장 비 및 무선 통신 등의 다양한 분야에서 상당한 발전 을 하여 왔으며 관심이 증가하고 있다 [9], [10] . [11], [12], [16] .…”

“…여기서 A: 펄스 진폭 : 0차 가우시안 포락선의 표준 편차   : 정현파 함수의 주파수 3.1～10.6 GHz에서 동작하는 기준 안테나의 경우 1미터 이격 거리는 레일레이 far 필드 조건식 (6)을 만족한다 [10] . 최소 신호 왜곡 관점에서 정규화된 가우시안 펄 스 여기 신호와 far 필드에서 수신된 정규화한 수신 신호와의 펄스 충실도는 UWB 안테나의 수신 신호 품질을 나타낸다 [18] .…”

Photonically implemented ultrawideband RF matched filtering

“…In recent years different techniques have been investigated and utilized to photonically generate ultra-wideband arbitrary waveforms [1][2][3][4][5][6][7]. The use of ultrafast optical pulse shaping followed by frequency-to-time mapping, via optical fiber dispersion, and optical-to-electrical conversion for the generation of arbitrary RF electrical waveforms has been demonstrated [1-2] which also enabled to synthesize matched waveforms to compensate ultrawideband (UWB) antenna link dispersion [8-9] and measure the frequencydependant delay of broadband antennas [10]. On the other hand photonic processing of radio frequency signals has been extensively investigated only as microwave spectral amplitude filters which enable bandpass filtering of microwave signals [11][12][13].…”