We have shown that strontium lanthanum aluminate (SrLaAlO4) has considerable potential as a substrate material for high-temperature superconductor (high Tc) microwave applications. Excellent lattice match is obtainable on a 14° tilt from the c axis. The lattice dimensions encourage ab plane epitaxial growth. The thermal expansion was found to be 7.4×10−6 °C−1. Patterned sputtered niobium resonators on SrLaAlO4 exhibit Q values at 5 K comparable to similar niobium resonators on polycrystalline alumina, (Q≳10 000 from 2 to 15 GHz). Deposited YBa2Cu3O7−x (YBCO) films on this substrate show sharp ac susceptibility transitions indicating good homogeneity and ab plane orientation.

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Two numerical methods are used to evaluate the integrals that express the em fields due to dipole antennas radiating in the presence of a stratified medium. The first method is a direct integration by means of Simpson's rule. The second method is indirect and approximates the kernel of the integral by means of the fast Fourier transform. In contrast to previous analytical methods that applied only to two‐layer cases the numerical methods can be used for any arbitrary number of layers with general properties.

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