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Linear Measurements
Published in Mike Golio, Commercial Wireless Circuits and Components Handbook, 2018
Determination of the relative locations of the minima and maxima along the line, or similarly the determination of the magnitude of waves traveling toward and away from the load resistor, is the basis for the measurement of RF and microwave impedance and the most basic instrument used for making this measurement is the slotted line. The slotted line is a transmission line with a slit in the side that enables a probe to be inserted into the transmission mode electromagnetic field as shown in Fig. 13.8. A diode detector placed within the sliding probe provides a DC voltage that is proportional to the magnitude of the field in the slotted line. As the probe is moved along the line, the minimum and maximum field positions and magnitudes can be determined. The ratio of the maximum field magnitude to the minimum field magnitude is the standing wave ratio (SWR). SWR is normally stated as a scalar quantity and is SWR=1+ρ1−ρ
Guided Fields
Published in Philip C. Magnusson, Gerald C. Alexander, Vijai K. Tripathi, Andreas Weisshaar, Transmission Lines and Wave Propagation, 2017
Philip C. Magnusson, Gerald C. Alexander, Vijai K. Tripathi, Andreas Weisshaar
Because the conduction current has no circumferential component, a longitudinal slit of infinitesimal width could be cut through the outer conductor without disturbing the field patterns. This is the basis of the slotted line, a useful experimental device for measuring relative field strength and thereby obtaining standing-wave data. An insulated probe connected to a crystal detector is used to sample the field. (For mechanical clearance the slot actually used is noninfinitesimal in width. An alternative cross section for slotted lines which is sometimes used in coaxial systems is the parallel-slab line, discussed in Appendix C.)
Testing Coaxial Transmission Line
Published in Jerry C. Whitaker, The RF Transmission Systems Handbook, 2017
Historically, a slotted line device has commonly been used to measure VSWR on a transmission line. A slotted line includes a probe that penetrates the outer conductor of the line through a slot. The probe, in close proximity with the inner conductor, measures the voltage or samples the field along the center conductor. The sample is detected, which results in a voltage proportional to the actual signal on the center conductor. It is an accurate, reliable instrument. However, the slotted line procedure takes a considerable amount of time to accurately sweep a transmission line over a wide bandwidth, and then to plot the resulting data.
Metallic ring backed co-planar waveguide satellite L-band and S-band low Pass filter
Published in International Journal of Electronics Letters, 2021
S. Oudaya coumar, Tamilselvan S
There is many more complex circuits with composite topology are presented in the literature (Jahanbakhshi & Hayati, 2016). The proposed L and S band filter topology yields enhanced results on par with those complex structures. The hybrid circular-ring resonator circuits can also be implemented in the form of transmission line model and waveguide structures. The choice of feed line, mode of coupling and category of resonator are subject to the application and operating frequency ranges. Maximum resonator topologies valued earlier are microstrip, circular/rectangular waveguide, co-planar waveguide and slotted line. However, the CPW structure is the best choice for tuning the bandwidth. The topology is optimised for satellite L and S band operating frequency.