This paper proposes a miniature 3D SIP (system in package) design of the four-channel RF transceiver. The Key advancement is the demonstration of 3D stacking of silicon carriers and ALN (aluminium nitride) HTCC carrier based on 70 um Au micro-bumps. The influences of the carrier on the performance of GaAs (gallium arsenide) MMICs are analyzed in detail. A new silicon carrier with hollow annular TSV and non-metalized cavity is proposed, which is characterized by less impact on MMIC performance, more compact stacking size and lower fabrication cost. The GaAs MMICs, silicon and ALN carriers are heterogeneous integrated and stacked vertically to form a 3D SIP. The proposed hermetic 3D SIP is highly integrated in a volume of 12.7 mm × 13.9 mm × 3.6 mm with 7 × 8 BGA (ball grid array) input and output ports, and capable of working with four different types of passbands for anti-jamming. Measured results indicate that the SIP has the advantages of high reliability, high performance and mass manufacture.

In this paper, an effective high order superconducting filter design technique is proposed. The key advancement is the demonstration of neural network HTS (high temperature superconducting) high order filter design for the first time. An artificial neural network (ANN) combined with the coupling matrix is used as a fast model of the high order superconducting filters. The initial filter layout is established and characterized by a set of geometric variables. The coupling matrix is extracted from the simulated response of the filter layout, and the ANN is trained to learn the relationship between the coupling matrix and the filter geometric variables. The well-trained neural network model can provide an accurate and fast prediction of filter performance with different input geometric variables in less than one second, which greatly improve the design effectiveness. The experiments show that there is an excellent match between the responses of the simulated data and those from the neural network. Compared with the conventional electromagnetic simulation method, this model is time saving especially in high-order filters design with complex undesired stray couplings.

This article proposes a novel dual-band filter topology by integrating two cascaded quadruplet (CQ) units and a dual-composite bandpass bandstop resonator (CBPBSR) unit. The CQ units generate out-of-band and in-band transmission zeros (TZs) to improve stopband roll-off, while the dual-CBPBSR unit introduces two TZs at the main passband center frequency $f_{0}$ to enhance inter passband rejection. This approach enables flexible control over the distribution of TZs and achieves excellent frequency selectivity. Based on this topology, a high-temperature superconducting (HTS) dual-band ultra-narrowband bandpass filter (BPF) is designed and fabricated using folded compact double-spiral microstrip resonators. The filter operates at 2533.25 ( $f_{01}$ ) and 2560.85 MHz ( $f_{02}$ ), both with a relative bandwidth of 0.44% at $f_{0}$ . Six TZs are realized, with a maximum out-of-band roll-off rate of 23.0 dB/MHz, insertion loss below 0.2 dB, and inter passband rejection of 60 dB. At 77 K, the measured results agree well with simulations, validating the proposed topology for high-performance ultra-narrowband dual-band filter applications.

By analyzing the mechanism of the Cul-de-sac topology to realize the response of the generalized Chebyshev response function, the principle of introducing the transmission zeros (TZs) of the transfer function is analyzed and discussed. Typical topological structure models and coupling matrices with different numbers of zeros and poles are extracted using the coupling matrix analysis method. By analyzing the tolerance and the magnitude characteristics of the coupling coefficient values of the filter's coupling coefficient, the suitability of the Cul-de-sac topology in high-temperature superconducting (HTS) filter applications is explained and elaborated. A Cul-de-sac topology HTS bandpass filter with a center frequency of 2345 MHz, a bandwidth of 50 MHz, and a pair of TZs was designed and fabricated on a 2-in-diameter 0.5-mm-thick MgO wafer with double-sided YBCO thin films. The machined physical circuit is then measured at 77 K, and the frequency response of the test results can be in good agreement with both the model applying the same principle and the frequency response of the full-wave electromagnetic simulation of the planar circuit. Therefore, the Cul-de-sac topology demonstrates the ease of implementation of coupling coefficients and good machining tolerance for the design of HTS filters.

This letter presents the new concept and method of feed line resonator (FLR). Unlike the conventional filter feed lines, which serve solely for external coupling, the proposed feed line resonators can not only introduce additional transmission poles within the passband, but also generate transmission zeros at both sides of the passband, thereby significantly augmenting the filter’s performance without enlarging its physical dimensions. A novel and systematic method for constructing multimode resonators, called the connected line resonator (CLR) method has been proposed, two parallel lines are connected to obtain three resonant modes for filter design. The key advantage of this proposed CLR is its ability to exhibit a substantial attenuation slope at the higher band edge. To demonstrate the FLR and CLR method, two wideband filters were designed based on the high-temperature superconducting film, with the center frequency at 7.3 GHz, and the fractional bandwidth of about 59%. The measured results agree well with the simulation ones.

By employing the synthesis method of the generalized Chebyshev function filter and the frequency-domain symmetric transformation of the transmission and reflection function response, the transformation from a single-passband filter to a symmetric dual-passband filter in the frequency domain is successfully achieved. The cascaded triplet (CT) unit features flexible control over transmission zeros (TZs), and the cascaded quadruplet (CQ) unit can introduce TZs in pairs in a single step. Based on the topology of CT and CQ units, a typical topological structure model and the corresponding coupling matrix of the dual-passband filter with specified TZ positions are extracted by the coupling matrix analysis method. A dual-passband high-temperature superconducting bandpass filter is designed with a folded compact dual-spiral microstrip resonator based on the afore mentioned design method. The filter has center frequencies of 2495.75 MHz and 2525.75 MHz, with two equal relative bandwidths of 0.86%@f ₀ and four TZs. The measured results of the filter at a temperature of 77 K show excellent sideband roll-off of ⩾12.8 dB MHz⁻¹ and minimal insertion loss of ⩽0.2 dB, which is consistent with the theoretical model and full-wave electromagnetic simulation frequency response. Thus, the effectiveness of the proposed topology and design method in achieving dual-passband characteristics and introducing in-band TZs is validated. Furthermore, this study provides an effective approach for designing high-performance ultra-narrowband dual-band filters.