Temperature compensation of resonators using different materials and suitable dimensions

The mode-matching method is applied to synthesize stepped combline resonators with a perfectly compensated temperature characteristic. Besides a convenient choice of materials, emphasize is put on the correct choice of the dimensions, to obtain a trade-off with the resonators quality factor. Several resonators have beer fabricated to verify the accuracy of the method. A 2.14 GHz, 9-pol filter was designed and measured. The temperature drift was improved from -47 kHz/K to 1 kHz/K.