A modern course in microwave engineering

Pozar, D.M.

doi:10.1109/13.53636

Cited by 190 publications

(262 citation statements)

References 5 publications

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“…The width of the host line (W host ) is not considered to be an optimization variable, since the value provided by well-known microstrip formulas [21] (giving the line width as a function of the characteristic impedance Z o and substrate parameters) are very accurate. The remaining parameter to be determined is the length of the host line, l. This is determined through another independent ASM iterative process, where the variable of the coarse model is the electrical length of the loaded line, i.e., l, rather than kl (the electrical length of the unloaded line).…”

Section: Second Asm: Determination Of the Layoutmentioning

confidence: 99%

“…Then the capacitance of this patch is inferred from the electromagnetic simulation by considering the ports indicated in Fig. 2(a), specifically by inferring the admittance of the shunt load [21], and it is compared to the target value. The matrix B, actually composed of a single element, is initiated by varying the patch dimension l p and recording the effects of this variation on the capacitance of the patch.…”

Section: Second Asm: Determination Of the Layoutmentioning

confidence: 99%

“…The dispersion relation and Bloch impedance of the structure of Fig. 1 can be obtained from the ABCD matrix of the unit cell, following standard Bloch wave analysis of periodic structures [21]. In particular, the dispersion relation is given by:…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis of slow-wave structures based on capacitive-loaded lines through aggressive space mapping (ASM)

Orellana

Selga

Sans

et al. 2015

Int J RF and Microwave Comp Aid Eng

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This paper is focused on the automated synthesis of slow-wave structures based on microstrip lines loaded with patch capacitors. Thanks to the presence of the shunt capacitors, the effective capacitance of the line is enhanced, and the phase velocity of the structure can be made significantly smaller than the one of the unloaded line. The target is to achieve the layout of the slow-wave structure able to provide the required slow-wave ratio, characteristic (Bloch) impedance and electrical length (i.e., the usual specifications in the design of slow-wave transmission lines). To this end, a two-step synthesis method, based on the aggressive space mapping (ASM) algorithm, is proposed for the first time. Through the first ASM algorithm, the circuit schematic providing the target specifications is determined. Then, the second ASM optimizer is used to generate the layout of the structure. In order to illustrate the potential of the proposed synthesis method, three application examples are successfully reported. The two-step ASM algorithm is able to provide the layout of the considered structures from the required specifications, without the need of an external aid in the process.

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Section: Second Asm: Determination Of the Layoutmentioning

confidence: 99%

Section: Second Asm: Determination Of the Layoutmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of slow-wave structures based on capacitive-loaded lines through aggressive space mapping (ASM)

Orellana

Selga

Sans

et al. 2015

Int J RF and Microwave Comp Aid Eng

View full text Add to dashboard Cite

show abstract

“…The copper tape worm sections are modeled as a dissipative transmission line with a frequency dependent resistance per unit length, R(ω). According to the standard transmission line model 16 , the local voltage between the two conductors, V (x), and the longitudinal current, I(x), are related by V (x) = V 0 e ±γ(ω)x and V (x) = ±Z 0 (ω)I(x). The propagation coefficient γ and line impedance Z 0 are given by γ(ω) = iωC(iωL + R) and (1)…”

Section: B Model For a Coaxial Geometrymentioning

confidence: 99%

Dissipative cryogenic filters with zero dc resistance

Bluhm

Moler

2008

Review of Scientific Instruments

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The authors designed, implemented and tested cryogenic RF filters with zero DC resistance, based on wires with a superconducting core inside a resistive sheath. The superconducting core allows low frequency currents to pass with negligible dissipation. Signals above the cutoff frequency are dissipated in the resistive part due to their small skin depth. The filters consist of twisted wire pairs shielded with copper tape. Above approximately 1 GHz, the attenuation is exponential in √ ω, as typical for skin depth based RF filters. By using additional capacitors of 10 nF per line, an attenuation of at least 45 dB above 10 MHz can be obtained. Thus, one single filter stage kept at mixing chamber temperature in a dilution refrigerator is sufficient to attenuate room temperature black body radiation to levels corresponding to 10 mK above about 10 MHz.

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“…Since a lossless mismatched circuit can be treated as an impedance transformer, which changes the noise source's 50-output impedance to the intended generator impedance, its bandwidth, as bounded by the Bode-Fano criteria [14], should be infinite. Conceptually, this can be understood by imagining a very long lossless tapered line that transforms a 50-impedance to some other real impedance over a very large bandwidth.…”

Section: Mismatched Circuit Implementationmentioning

confidence: 99%

A Novel Wide-Band Noise-Parameter Measurement Method and Its Cryogenic Application

Weinreb

2004

IEEE Trans. Microwave Theory Techn.

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Abstract-The concept of using a long mismatched transmission line to measure noise parameters has been known for some time. However, it has been limited to narrow-bandwidth applications, and a wide-band extension has never been reported. In order to measure the cryogenic noise parameters of a wide-band low-noise amplifier (LNA), a wide-band frequency-variation method is proposed. In this method, the four noise parameters at each frequency are derived numerically from a set of matched and mismatched noise temperatures measured within a surrounding frequency-sampling window. By scanning this frequency-sampling window, noise parameters over a wide frequency range can be obtained. Since this approach can be easily incorporated into existing noise measurement systems, a tuner is not required, and the technique can be applied to a cryogenic amplifier. This paper details the theory, implementation, and verification of this new method. The measured noise parameters of a cryogenic wide-band LNA are presented.Index Terms-Frequency-variation method, noise-parameter measurement.

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A modern course in microwave engineering

Cited by 190 publications

References 5 publications

Synthesis of slow-wave structures based on capacitive-loaded lines through aggressive space mapping (ASM)

Synthesis of slow-wave structures based on capacitive-loaded lines through aggressive space mapping (ASM)

Dissipative cryogenic filters with zero dc resistance

A Novel Wide-Band Noise-Parameter Measurement Method and Its Cryogenic Application

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