Comparison of Three Methods for the Measurement of the Differential Impedance of a Balanced Device [Measurements Corner]

Abstract

Three methods for the measurement of the differential impedance of a balanced device are evaluated: 1) the S-parameter method, 2) the balun method, and 3) the mixed-mode S-parameter method. An emphasis is given to the choice of combinations of fi ve two-port standards for the balun method. Each of these methods was used to measure the known differential impedance of a broadband balanced load, and the unknown differential impedance of a narrowband balanced microstrip patch antenna. These methods and the obtained experimental results are discussed.

Novel input impedance analysis of differential feed microstrip antennas using the bi‐characteristic‐impedance transmission line (BCITL) model

“…The impedances of differential antennas can be calculated systematically in terms of the two-port network parameters. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] In the studies by Tu and colleagues, 12,13 the analysis of the impedance relationship of a rectangular patch antenna with a differential feed is provided. The impedance of differential antenna for both differential and common modes can be characterized by measuring associated scattering parameters.…”

“…Since practical antennas are low loss, the BCITL can be effectively employed to model low-loss antennas to understand physical mechanisms better. It will be shown that the novel BCITL model can simplify impedance relationships for differential microstrip antennas, compared to the previously published methods based on the two-port network parameters, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] with accurate results and better physical insights. To validate the proposed model, simulation, and measurement results are compared.…”

“…The impedances of differential antennas can be calculated systematically in terms of the two‐port network parameters 1–18 . In the studies by Tu and colleagues, 12,13 the analysis of the impedance relationship of a rectangular patch antenna with a differential feed is provided.…”

Differential Antennas: Fundamentals and Applications

“…In the circuit community, the terms of differential and single-ended circuits prevail over those of balanced and unbalanced circuits [13]. Therefore, it is better for integrated antenna designers to adopt the terms of differential and single-ended antennas to avoid any potential misunderstanding from integrated circuit designers [14]- [39].…”