# Miniaturized Compact Reconfigurable Half-Mode SIW Phase Shifter with PIN Diodes
###### Abstract  
In this work, a novel electrically reconfigurable phase shifter based on a half-mode substrate integrated waveguide (HM-SIW) is proposed. SIW is a guided transmission line topology, and by using half-mode excitation, a smaller size can be achieved. Phase shifters are electronic devices that change the phase of transmission for a wide range of applications, including inverse scattering and sensing. The tunability of PIN diodes is applied here to achieve a reconfigurable design. The proposed single-layer structure does not require extra wiring layers for the bias circuit on the suggested printed circuit board. Its principle consists in the integration, in the HM-SIW, of three parallel lines, each connecting the edge of the HM-SIW and linked to a PIN diode and a radial stub. Here we present the results of measurements for a frequency band from 4.5 to 7 GHz that demonstrate how the experiment agrees with simulations. Insertion loss was less than \(-10\) dB, and port coupling was less than \(-2\) dB for both simulation and measurement solutions. The proposed half-mode structure is around half the size of a typical SIW line. With the proposed design, the seven states of the PIN diodes can be validated (ON and OFF), with a wide band adaptation and a relatively constant phase difference across a broad frequency range (44%). A key benefit of the proposed design for a microwave component is the reduction of extra biasing layers for the PIN diodes. This is in addition to the reduced size of the transmission line compared to a commercial SIW. In the annexed section, simulation software is used for a more comprehensive analysis involving more phase shift values and parametric studies. electronic phase shifter; half-mode; PIN diodes; miniaturized size; reconfigurable microwave device; SIW +
Footnote †: journal: _technologies_  
has been proposed by comparing two different transmission lines for two distinct phase shifts [19]. A more complex structure has been applied to design a tunable filter phase shifter at 1 GHz frequency with two power dividers and two reconfigurable filter couplers [20]. Additionally, substrate-integrated waveguides (SIW), as a new generation of transmission lines [21; 22; 23], can be configured for phase-shifting microwave networks [24; 25; 26]. Added metal posts to change SIW resonators [24], slots on the upper surface of the SIW [25], high dielectric constant perturbation [26; 27], fixed cross-sectional elements [28], and coupled slots [29] are some of the models presented to develop a SIW phase shifter. Many of these methods generate a fixed phase difference between two points in the microwave component. However, it is highly desirable to create a modular or reconfigurable phase shifter device. In particular, a compact and miniaturized element is required that can be easily integrated with other microwave-packaged components. By using a diode and its related states, one can tune the constant phase shifter structure as studied in [30; 31]. The PIN diodes can interact with the SIW line to change the required phase difference while the signal travels through the line. Integration of diodes in an electromagnetic device is not straightforward and requires innovative aspects regarding diode state change. An example of a technique presented in a patent from 2022 involves eliminating the need for additional biasing lines for PIN diodes used in beam switching applications [32]. This algorithm is suggested to generate a phase shifter microwave component in this novel progressive work. The intervention load parameters may also be modified by using a varactor and capacitor in addition to the PIN diodes [33; 34; 35]. However, a PIN diode could provide a more stable and quicker response to bias and RF sources. With a tapered microstrip choke and resistor in one united layer, radio frequency (RF) signals and DC current are isolated [36]. In order to separate two energy sources and their functionality, this step must be taken.