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Item type:Publication, Access status: without files , A Compact K-/Ka-Band Waveguide Transition with Integrated Diplexer and Power Divider(2021-04); ; ; ; The component presented in this work combines three functionalities, i.e., a waveguide transition, frequency separation, and power division. A rectangular waveguide (RWG) serves as common 20/30 GHz port. The signals are diplexed into two 20 GHz and four 30 GHz grounded coplanar waveguides (GCPWs). The required 3 dB and 6 dB power division ratios are achieved reactively and by exploiting symmetries. Both passbands feature a -10 dB reflection bandwidth of more than 1.2 GHz, an insertion loss below 1.3 dB, an isolation exceeding 25 dB, and an amplitude imbalance of less than 1 dB. The component occupies only 9 x 9 mm2 on a single layer printed circuit board (PCB) and is thus suitable for application in highly integrated phased array front-ends.Publicationtype: Conference Paper42 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A Heterodyne Transceiver With Integrated Calibrator for K/Ka-Band Phased ArraysThis work presents a heterodyne K/Ka-band transceiver with integrated transmit (Tx)/receive (Rx) calibrator for satellite communication terminal antennas. To reduce the system complexity, the circuit features only three active mixers compared to four in conventional designs, which is also beneficial in terms of power consumption. The signal distribution requires a radio frequency (RF) switch, a local oscillator (LO) diplexer, and a power divider. The transceiver interfaces the back-end circuitry with merely three intermediate frequency (IF) signals and a dual-tone LO signal. Despite the reduced system complexity, it provides full-duplex communication at 20 GHz (Rx) and 30 GHz (Tx) as well as sequential calibration for the Rx and the Tx antennas. The demonstrator realized in standard printed circuit board technology is compact enough to meet phased array requirements and fully verifies the desired functionality.Publicationtype: Conference Paper120 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A Self-Diplexing Dual-Polarized K-/Ka-Band Patch Antenna(2021-04); ; This paper presents a self-diplexing microstrip patch antenna (MPA) for dual-band operation in the satellite communication bands around 20 GHz and 30 GHz. By providing two orthogonal linear polarizations in both bands, left and right circular polarization (CP) can be generated with proper external circuity. The footprint of the antenna is smaller than 5x5 mm2. It thus fits in half the free space wavelength grid at 30 GHz, as imposed by array physics for wide grating lobe free scan ranges. The antenna is realized with only four layers in standard printed circuit board (PCB) technology. Its -10 dB-reflection bandwidth reaches 0.6 GHz and 1.25 GHz around 20 GHz and 30 GHz, respectively. The port isolation is better than 15 dB in the lower and 25 dB in the upper band.Publicationtype: Conference Paper89 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A 9-Channel Phase Coherent Receive System for Direction of Arrival Estimation(2022-04); ; ; ; Collapsed buildings are a common occurrence after earthquakes, but are also commonly caused by gas explosions. The survival chance of buried victims is heavily dependent on the time it takes to locate and rescue them. This paper introduces a 9-channel phase coherent receive system intended for direction finding in search and rescue applications. The motivation for this system is to minimize the time necessary to locate the buried phones of victims. The design consists of an FPGA based digital system with high speed I/O for data acquisition and signal processing, as well as nine synchronized receivers each covering the entire target bandwidth. A high phase resolution is achieved down to very low input levels.Publicationtype: Conference Paper84 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Amplifier Bias for Minimum Noise Figure in Thermally Constrained SystemsThe noise figure of low noise amplifiers (LNAs) critically depends, amongst others, on the biasing conditions and the transistor temperature. The latter may be constrained by the performance of the cooling system, in particular its thermal resistance, and the ambient temperature. This paper reports as a case study how the noise figure can be minimized in such constrained systems by properly adjusting the biasing conditions. For this, the two-dimensional noise figure dependence on the temperature and the drain current is measured for a commercial LNA. For a systematic mathematical treatment, the measured data are interpolated by means of two black-box models. In contrast to the first one, which requires the noise figure to be measured in a climate cabinet, the second one only necessitates room temperature data in addition to commonly available data sheet values. It is shown, that, depending on the thermal resistance of the cooling system and the ambient temperature, i.e., two constraining system parameters, an optimal drain current setting may reduce the dissipated power by up to about 50 % compared to the nominal data sheet value. As this lowers the heat load and, in turn, the device temperature, the noise figure can be improved by up to 0.4 dB.Publicationtype: Conference Paper70 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A Compact Filter With Dual-Mode Folded Circular SIW CavitiesThis contribution presents a compact filter with a novel folded circular substrate integrated waveguide (FCSIW) cavity. A modification leads to dual-mode operation. Two of these cavities are combined to form a fourth order filter. The design idea is experimentally verified with a very compact 10 GHz filter featuring an insertion loss below 2.4 dB in a 1 GHz bandwidth. The out-of-band rejection exceeds 40 dB between 11.1 GHz and 30 GHz.Publicationtype: Conference Paper44 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A K/Ka-Band Front-End for Dual-Beam, Dual-Polarized Tx/Rx Phased ArraysThis work proposes a front-end in printed circuit board technology (PCB) for phased array terminal antennas at K/Ka-band. The front-end enables full-duplex transmit/receive (Tx/Rx) operation for two polarizations. It supports a single Tx beam and simultaneously two independent Rx beams. The beamforming networks (BNs) are realized with commercially available active semiconductor circuits. Two separate BNs and low noise amplifiers (LNAs) are needed for Rx. Diplexers realized in substrate integrated waveguide (SIW) technology ensure a high Tx/Rx isolation. Thanks to its compactness, the circuit satisfies the half-wave element spacing requirement imposed by array physics for both, Tx and Rx. The measured Rx noise figure remains below 2 dB and the single channel Tx output power exceeds 9 dBm.Publicationtype: Conference Paper153