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This paper provides the guidelines for the practical development of novel advanced test beds for passive intermodulation (PIM) measurements. The proposed test beds are highperformance and flexible, allowing for the measurement of several PIM signals of different orders, with two or more input carriers. In contrast to classic test beds for satellite hardware, based on the cascaded connection of several elements, an integrated solution involving the minimum number of hardware pieces is proposed. The result is a lower number of flanged interconnections thus reducing residual PIM level and insertion losses. In addition, return loss degradation and harmful spurious generation in the interconnections are also avoided. Measurement test beds for conducted and radiated PIM, in both transmitted and reflected directions, are discussed, highlighting the benefits and drawbacks of each configuration. Design guidelines for the key components are fully discussed. Illustrative application examples are also reported. Finally, excellent experimental results obtained from low-PIM measurement setups, working from C band to Ka band, are shown, thus fully confirming the validity of the proposed configurations. Index Terms-Intermodulation distorsion, microwave filters, high-power filters, multiplexing, computer-aided engineering. I. INTRODUCTION I N the last decades, the avoidance of passive intermodulation effects (PIM) has become a top-priority issue for communication satellites systems engineers, as a consequence of the ever more demanding payload requirements [1], [2]. PIM may, in fact, become an important source of performance degradation due to increased transmitted power levels for higher capacity links, together with the need for simultaneous operation in transmission (downlink) and in reception (uplink) at different frequency bands [3], [4]. In the scenario of Manuscript

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The design and first experimental results of Tx and Rx L-band bandpass filters for a high-power satellite diplexer are presented in this paper. Designed in the framework of an ESA ARTES AT project, the filters are based on TM010 mode dielectric resonators. These resonators allow for better results in terms of volume occupation with respect to other dielectric resonators still maintaining high Q-factor values (>2000). Volume saving above 30% is achieved with respect to standard coaxial filters. The filter geometries and materials have been chosen in order to improve the power-handling and to cope with related critical issues for space applications (i.e. avoid any multipactor discharge in the operating RF power range and low-PIM response). Measurements of Tx filter show good correlation with the design in terms of central frequency, BW, and unloaded Q-factor (almost 3000). Measurements of Rx filter show a worse correlation with the design in terms of filter response shape. This is ascribed to size tolerances of one of the filter resonators. Multiple analyses are ongoing to remove this degradation in the final engineering model.

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